Pricing is a major issue in private-label sales arrangements. In order to make money after paying all the marketing and sales costs, a manufacturer has to be able to buy a private-label product at about 30 percent of the final retail price. That means your profit margin on private-label sales will be slim--but you'll still earn more than you would selling your product part-time.
Don't stop trying to come up with new inventions just because you're short of time. If you set up a private-label agreement, you can sell your product with a minimum of effort. You'll generate part-time income and begin building a track record of success that will make it easier to sell future inventions.