1. Buy underpriced used books. Outfit a phone or PDA (personal data assistant) with a scanner, scan the ISBN numbers of books at used bookstores and thrift shops, and compare the asking prices with what the books are selling for on a site like Amazon. Whenever you get a good hit (which won’t be often but, since the process is fast, won’t take long, either), buy the book and resell it online. Be discreet about this, as the store managers probably won’t like what you’re doing.

2. Bargain-hunt at yard and thrift sales. If you have a bit of knowledge in a particular area (ex. Taxco Mexican silver, action figures, classic National Geographics) or even just a good eye for quality, visit private sales early and often to find unexpected deals.

3. Go to police auctions. You can find incredible deals here, and though may not be able to resell a car that was involved in a serious crime, you can probably find some spectacularly cheap jewelry that someone else would be happy to buy off you.

4. Refinish ratty furniture. If you have lacquer thinner, sandpaper, stain, and some craft sense, you can buy worn-out furniture and fix it up for a great resale price.