Because nobody on Craigslist ever seems to answer your WANTED ad for a retired circus monkey with slightly above average masonry skills, why not hit up Peddl: a just-launched virtual flea market from three MIT Media Lab dudes that streamlines the whole "I want/ you have" process by broadcasting posts/ responses and instantly connecting buyers & sellers via text and phone calls where your number's withheld, so definitely start out by asking them if their refrigerator is running.
After signing up, you have three options: 1) search for a specific item (new couch, pre-owned Huffy, slightly used Murphy bed, etc.); 2) browse a local Gmap populated by the (sortable by price/ product) wares your neighbors are seeking/ unloading; or 3) upload an "I Have/ I Want" post (no sex, fireworks, or bodily fluids, you crazy kids) with the price/ amount you're willing to pay. From there, Peddl will either notify you when a match is found or, if you do end up stumbling across Carlos Quintana's rookie card, you can instantly chat/ call for more deets (Is it a Donruss Rated Rookie?), negotiate a price, agree to the sale, or arrange a pickup location, at which point you can settle up in cash or by using the one-touch secure online payment system.
Because everything is easier when you're not tethered to your Gateway, there's also a handy iPhone app, as well as the option to link everything to FB & Twitter, ensuring your friends know you're finally going to get that veneer-wall-building monkey off your back.