When you learn to sift out the values in other people's discards, yard sales become treasure hunts. The key is knowledge.
"With knowledge, you have the upper hand and can actually identify what is valuable," says Aaron LaPedis, author of "The Garage Sale Millionaire."
If you don't know about a particular item, you can look it up on your smartphone, he says. LaPedis recommends searching through the "completed" section of eBay to see the price a specific item has garnered. On the left panel under "show only," click on "completed listings." Then under "buying formats," click the box next to "auction" to find out the sale price.
"You never know what you're going to find while visiting yard sales, so take a large enough vehicle to hold the big items," LaPedis says. "And if you don't see what you want, ask if they have it. You'll find some gems that way."