Thousands of Maine entrepreneurs are using online auction services as a central part of their business models, competing with companies already using the Internet to entice customers.

Small businesses are the “bread and butter” of eBay’s revenue, said Brian Dancause, manager of small-business assistance in the state Department of Economic and Community Development.

The California-based Internet auction company has created a service allowing entrepreneurs to set up electronic “storefronts” where transactions are completed immediately, instead of after weeklong auctions.

Bill Cartmel of Lewiston, who runs a Web site offering vintage records, antiques and memorabilia, said he has 95 percent of his inventory listed on his electronic storefront, which has led to greater profits and reduced fees.

“Six years ago, I started selling on eBay on the weekends and started doing pretty well, but now I do it full time,” said Cartmel, who said he grosses more than $100,000 a year selling goods online.

Still, entrepreneurs are finding other uses for the Internet auction service.

Susan Robbins in Portland uses eBay for the majority of her business. Allowing consumers to bid on the vintage clothing she sells drives up prices and provides her with greater profit than she could earn selling clothing from a brick-and-mortar storefront.

Other Maine merchants use eBay as an advertising tool. Betsey Hanscom doesn’t have a huge marketing budget she can tap to inform consumers of her animal-shaped, microwaveable heating pads she designs from her home in Lewiston, so she makes sure her products are listed on eBay in as many categories as possible.

“I list my items on eBay almost as an inexpensive advertisement,” Hanscom said. “A lot of times people won’t bid on my items but will see the company name.”