Just as the title says, I've been doing this a lot recently. It used to be that there was a minor difference between an item being sold as a Buy it Now and an Auction price. Usually BINs (Buy it Now) have been about 10% higher, the actual percentage depends on the category. This discrepancy is for the simple fact that people will pay a couple dollars more for something if they don't have to mess with bidding or more importantly, wait to purchase the item. People want things NOW. Buy it now, is just like it sounds, a seller has set a specific price they want for the item and the buyer buys the item, pays, and that's the end. Now, an auction price can actually be 30% lower or MORE than the items commonly found "Lowest Price + Shipping BIN" price. If you find a niche you know a little something about (Mine being graded comics, car parts, department 56, vintage toys, etc) you can actually make a lot of money, every day, but its important to branch out because you can easily oversaturate the market, driving your profit down and meanwhile more savvy eBay sellers who DO use a BIN regularly will try to undercut you... so I recommend not focusing on a small category too long. 30% sounds really low of a profit margin, and it is, it leaves you with 10% to 20% of a profit range so they key is to bid on several different things at once to resell. If you are selling 10 items a day, its really not hard to make some decent money doing this. TIP: Find items that end at auction from 11 PM - 9 AM Sunday - Thursday night. You don't want to buy on the weekends because there actually is a noticeable spike in buyers/bidders, driving prices up and profit down. If you are pretty sure on the BIN value of an item, you can set a max bid of 60% of the total BIN value price and just pay for it in the morning. If you find something you like, check out the sellers other items so that you can go after their combined shipping. As soon as you pay, relist the items up at a BIN for 1% less than the item is currently selling for from another seller as a BIN. I commonly have things sold a day before or the day of getting these items in the mail. I cut open the packages, retape, print out a label, and its send back out to my customer within 24 hours.