It is estimated that more than 500 URLs have been bought and sold for $1 million or more.

We scoured domain name resource DN Journal and put together a list of documented million-dollar, domain-only sales. Some have been squatted on for 20 years and have only recently traded hands.

Not surprisingly, sex- and gambling-related domains are some of the biggest money makers.

Below, check out the most expensive domain names of all time.

Note: Web businesses have other assets and are not domain-only sales, so they were not eligible for this list. For example, Insure.com was bought for $16 million as a fully-operating, profitable company. DN Journal reports only the domain names sold after 2003 because prior sales are not verified by credible sources. 

MM.com — $1,200,000

Image credit: MM.com

Date sold: July 2014

MM.com was sold for $1.2 million through Sedo in July 2014. It was purchased by Hangzhou Duomai E-Commerce Co. Ltd, a company behind other domain names Game.com, JZ.com and 4.cn.

eBet.com — $1,350,000

Image credit: eBet.com

Date sold: October 2013

A man named Rick registered eBet.com in 1996 and held onto it until September, when he agreed to sell the domain.

"Network Solutions contacted me on August 29th with a $50,000 offer. I did not think anything of it, as I get these all the time," Rick wrote on his blog. "I countered at $1.8M and went about my business. On September 3rd voila the buyer comes back at $1MM ... So I think, how to get that number where I can live with and at the same time they can live with. So I counter at $1.35MM and that was my final offer. I hear nothing until the following Friday. September 16th. They accept the offer!"

Cameras.com — $1,500,000

Image credit: Cameras.com

Year sold: 2006

"Cameras.com attracted the highest bid in the live domain auction conducted by Moniker.com at the recently concluded T.R.A.F.F.I.C. East Conference in Hollywood, Florida," The DN Journal wrote in 2006.

"The winning bidder, Sig Solares (the CEO of Parked.com), wasted no time ponying up the $1,500,000 due, making that domain the first from the live auction that we have seen change hands."

Russia.com — $1,500,000

Image credit: statigr.am/jenaschultz

Tandberg.com — $1,500,000

Image credit: Tandberg.com

Year sold: 2007

"Tandberg Data, a leading global supplier and manufacturer of backup and archiving solutions, decided to take the cash offer for Tandberg.com from Tandberg, a leading global provider of visual communication products and services with dual headquarters in New York and Norway," The DN Journal wrote at the time of the sale.

The deal was actually completed in December 2006 but wasn't made public until early 2007.

Ticket.com — $1,525,000

Image credit: Ticket.com

Year sold: 2009

Ticket.com raked in a lot of cash for Afternic.com when it was sold off in October 2009. BuyDomains brokered the transaction.

DataRecovery.com — $1,659,000

Image credit: DataRecovery.com

Year sold: 2008

Minnesota's Associated Computers Inc. sold the domain to ESS Data Recovery on Feb. 1, 2008. ESS had been trying to buy the domain for a long time.

Auction.com — $1,700,000

Image credit: Auction.com

Year sold: 2009

Auction.com was rumored to be selling for even more money — $2.5 million. But it came in at $1.7 million after being purchased by Real Estate Disposition Corp.

Dating.com — $1,750,000

Image credit: Dating.com

Year sold: 2010

Dating.com was acquired at the at DOMAINFest auction in Ft. Lauderdale, Florida, in May 2012. The next-highest domain name to go at that auction was Boardgames.com, for $450,000.

Fly.com — $1,760,000

Image credit: Fly.com

Year sold: 2009

Travelzoo spent big bucks on Fly.com in January 2009.

Seniors.com — $1,800,000

Image credit: Seniors.com

Year sold: 2007

It was a big 2007 for a man named Page Howe. He sold two domains that year for seven figures. Besides Seniors.com ($1.8 million), he sold Guy.com for $1 million.

37.com — $1,960,800

Image credit: 37.com

Date sold: March 2014

37.com was sold for $1.9 million during a private sale in March. The domain was purchased by Chinese gamemaker 37Wan.

Computer.com — $2,100,000

Image credit: Computer.com

Year sold: 2007

In October 2007, Computer.com cleaned up at the T.R.A.F.F.I.C. / Moniker domain name auction. WallStreet.com was almost sold for $3 million there, but it didn't "meet the set reserve prices," according to DomainRich.

114.com — $2,100,000

Image credit: 114.com

Date sold: July 2013

114.com was sold privately for $2.1 million in mid-2013. It was bought by a Chinese company.

KK.com — $2,400,000

Date sold: November 2013

KK.com was sold through the Moniker/SnapNames brokerage firm for $2.4 million in late 2013.*

*An earlier version of this article incorrectly stated that the domain was owned by the Castello Brothers. 

Youxi.com — $2,430,000

Image credit: Youxi.com

Date sold: March 2014

Youxi.com (which means "games" in Chinese), sold for $2.4 million in a private sale in March 2014. It was purchased by Gamewave Group Limited.

Investing.com — $2,450,000

Image credit: Investing.com

Year sold: 2012

Forexpros.com bought Investing.com in late 2012 for $2.45 million. It was the largest domain sale of the year.

Social.com — $2,600,000

Image credit: statigr.am/daffodilflores

Year Sold: 2011

Moniker brokered a deal to sell social.com for $2.6 million in July 2011.

CreditCards.com — $2,750,000

Image credit: CreditCards.com

Year sold: 2004

ClickSuccess L.P., a firm that sells financial tools and products online, purchased CreditCards.com in 2004. It was the biggest domain-only sale in years. Casino.com was part of a massive $5.5 million deal in 2003, but its sale included a number of other assets.

Shopping.de — $2,858,945

Image credit: Shopping.de

Year sold: 2008

Unister GmbH purchased the domain to go along with its portfolio of other destination sites, including Auto.de, News.de and Kredit.de.

Candy.com — $3,000,000

Image credit: Candy.com

Year sold: 2009

G&J Holdings purchased Candy.com for a sweet $3 million in 2009. Toys.com outdid that earlier in the year, though, when it was bought by Toys"R"Us for $5.1 million.

Vodka.com — $3,000,000

Image credit: Vodka.com

Year sold: 2006

A billionaire in Russia who founded the country's largest vodka maker purchased Vodka.com for $3 million in December 2006.

Sex.xxx — $3,000,000

Date sold: June 2014

Sex.xxx is the most expensive .xxx domain name. In June it was sold for $3 million through ICM Registry. Barron Innovations bought it as part of a larger $5 million deal with ICM Registry that includes more than 40 keyword domain names.

Whisky.com — $3,100,000

Image credit: Whisky.com

Date sold: March 2014

Whisky.com was sold by Castello Cities Internet Network in a domain-only sale, and it was purchased by Michael Castello 19 years ago, in March 1995 when it cost nothing to obtain.

"I had the original registration in March of 1995, and I registered it for free," Castello wrote in DN Journal. "I always liked Scotch whisky, but the real reason I registered Whisky.com was because of the Whisky a Go Go night club in Hollywood. I always enjoyed “The Whisky”, with its musical heritage and scene where the likes of The Doors and Janis Joplin played. Years later, I even offered Whisky.com to the owner’s son and he told me he didn’t need it since they already registered WhiskyaGoGo.com. That rejection would prove to be good for me."

MI.com — $3,600,000

Image credit: MI.com

Date sold: April 2014

China's Xiaomi purchased MI.com in the biggest domain sale so far in 2014 during a private sale. It's said to be the most expensive domain name purchased by a Chinese Internet company, and Xiaomi intends to use it to make its brand name easier to remember.

IG.com — $4,700,000

Image credit: IG.com

Date sold: September 2013

Igloo/NetNames helped sell IG.com for almost $5 million in September 2013. It was purchased by London's IG Group; it was previously owned by Brazil search engine iG.

Medicare.com — $4.8 million

Image credit: Medicare.com

Date sold: May 2014

eHeathInsurance.com paid $4.8 million for Medicare.com earlier this spring. It paid $4.3 million in cash and $300,000 in debt, according to Domain Name Sales Report.

Clothes.com — $4,900,000

Image credit: Zappos.com

Year sold: 2008

Zappos coughed up almost $5 million for the domain Clothes.com. Now both are owned by Amazon.

Toys.com — $5,100,000

Image credit: Toys.com

Year sold: 2009

Toys"R"Us paid just over $5 million to have the powerful domain name, just months before Candy.com was acquired for $3 million.

Slots.com — $5,500,000

Image credit: Slots.com

Year sold: 2010

As TechCrunch pointed out at the time of the sale, that is more than $1 million per character.

Diamond.com - $7,500,000

Image credit: Diamond.com

Year sold: 2006

Odimo.com handed over the domain to an online jewelry retailer, Ice.com, in a private sale for one of the priciest domain name swaps of all time.

Porn.com — $9,500,000

Image credit: Youtube

Year sold: 2007

At the time of its sale, Porn.com was the biggest all-cash transaction for a domain name and the second-largest domain sale behind Sex.com's million exit. Moniker helped sell the domain to MXN Limited.

Fund.com — $9,999,950

Image credit: Fund.com

Year sold: 2008

Clek Media brokered a deal that few people believed was real: Fund.com was purchased in an all-cash deal in 2008.

Sex.com — $13 million

Image credit: Snob Models | Flickr

Year sold: 2010

Sex.com entered the Guinness Book of World Records for the highest domain-only sale in history. Escom LLC sold it to Clover Holdings Ltd.

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