What other ways can I advertise my business on a nonexistent budget?

If you want to run a thriving business, there has to be some kind of investment in getting your tools developed correctly (logo, website, business card, promo piece). Once they are in place, there are a host of things you can do on a lean budget. Have you tried contacting people who have complimentary businesses and asking to cross-link sites?

Have you evaluated  the other online portals you mentioned? Are they, in fact, the right choices for the folks who would be your best customers? Once that's established, you should evaluate the content that you posted about what you do. Perhaps the info needs to be tweaked.

You say you've been doing word of mouth advertising--is that through networking? Remember that even with all the free online vehicles out there, good old-fashioned, face-to-face networking and follow-up can work wonders for lagging sales.

Also, regarding your website: There's so much that could be wrong with it, especially if you did not have it done by a pro. Do you have a brand, and is that brand (with a unique, professionally designed logo and your distinctive colors) meaningful to the markets you are seeking to engage?

If your look is "homemade" rather than "businesslike," this could be holding you back. If your website doesn't have strong coding (with correct keywords, meta and title tags in the the back end) and meaningful content that the consumer sees; if people are confused about what you do or why they should want to do business with you--all these factors can impede your sales efforts.

Best of luck in getting things rockin'!
Pattie Simone