Really, is there anything to not love about the Internet? With just a few clicks of the mouse, we can download Kelly Clarkson’s “Walk Away,” order that cute Pottery Barn 17-slot frame with no shipping costs, and teleconference with the London office, all at the same time.

But something else that has become easier, thanks to the Internet, is making some extra money. And that’s something that we might need a little more than another Kelly Clarkson song.

Of course, the preeminent site for hocking just about anything is eBay. With the option to sell things for a specific “BUY-IT-NOW” price or place the item into auction, eBay can sometimes produce a surprising windfall for stuff you never thought would be worth so much.

“eBay's [like] a high-tech garage sale for me,” says Shane Scalisi, a 28-year-old web developer. “And selling my old computers has been the most profitable. For example, recently I sold a 2-year-old Dell laptop for more than it cost me to purchase a new one.”

But while many of us have sold the occasional handbag online for some quick margarita money, have you ever considered taking the selling one step further and really cashing in on an easy-to-use online seller’s site?

Ronni Creel, 27, is definitely cashing in. She earns about $4,000 a month via an eBay-based business selling vintage clothes. “I was working long hours as a store manager for a nonprofit thrift store and some customers came in looking for vintage or designer clothing to sell on eBay,” says Creel. “Since I was technically savvy and fashion-conscious, and craving more control over my own life, I decided to try it myself.”

Creel visits thrift stores and estate sales on weekends, looking for items-of-old that are trendy today. “I try not to pigeon-hole our business into 'just dresses' or 'just shoes' or 'just small sizes,' and we buy anything that we think someone somewhere is looking for,” Creel says. “[From] accessories to men's blazers to women's vintage dresses—anything goes!”