Online classifieds sites like Craigslist are basically virtual yard sales. Both require some shopping savvy. Style mavens Elizabeth Mayhew and Suzanne Nussbaum offer their lessons learned.
Only search online when you are on the hunt for something specific. You don't want to buy just to buy. When there's something you want, search once a day. Any less and you will worry about missing out on things; any more and you might make yourself crazy. Bookmark furniture sites that you check every few days and check the Craigslist app daily.
Do your homework. Study competing sites, including etsy.com as well as curated sites like 1stdibs.com, chairish.com and chairloom.com. The curated sites are particular about what they sell (usually the items are more expensive and better quality), so you won't typically find bargains, but the more you see, the more educated you will be.
Always take a tape measure with you when viewing furniture. People don't always post dimensions, and even if they do, they might not be accurate. Measure your door frames and, if applicable, stairwell or elevator, to make sure you can get your purchases inside your home.
Be open to bargaining. Some sellers add a prebargaining markup because they know that for many buyers, bargaining is part of the game. But not everyone is comfortable with haggling. Nussbaum says that she "doesn't have that skill set." Instead she looks only at items offered at a price she would be willing to pay in full. "I know a lot of people consider bargaining part of the game, but I find it so much more pleasant when everyone is just upfront to begin with."
Act quickly. Craigslist is about striking while the iron is hot. Chances are if you are interested in an item, so are a lot of other people. Plus, many sellers want to sell their stuff quickly — for them it's less about making money than it is getting the items out of their house.
Unless you're buying from a dealer, be prepared to pay in cash, and ideally with exact change. For a big purchase like a sofa, you should know your ATM's daily withdrawal limits and either take out money ahead of time or go to the bank.