I enjoy buying and selling on Craigslist. Since I moved to a more remote location, I've had to be creative. I work in Bakersfield, so I can bring items to town and meet up after work. I can buy the same way.
As a seller, I generally restrict my sales to the local area, unless it's a big ticket item. It pays to research market prices. I had a four-seat ATV that was VERY low hours and miles, and I advertised it up to 300 miles away. Buyer came from 250 miles away, when he called, he asked if I'd take less and my reply was "Cash talks. You know what it's worth, let's make a deal." He brought cash, negotiated a deal and took it home. Easy deal, and I tossed in a still-in-the-box cover and a couple helmets - after the deal was done. Made the buyer extra happy. Sold my damaged 16' landscaping trailer in two days, only listed on local CL, no phone negotiation, cash deal, happy buyer and seller. Wanted him to see the damage before negotiating. Had to take over the loan on a Tundra 4x4 Double Cab. Had about $8k in body damage. Took several pictures and posted ad on CL from Fresno to Los Angeles. My phone was blowing up within an hour - and every caller had a Middle-Eastern accent and was a dealer. Told six of them what the bottom price was, and that I had lots of interest. Had two of them waiting in my work parking lot after work, first one there wanted a lower price - until I turned toward the second one. Sold it right then.
As a buyer, again it pays to know market prices. My wife decided she wanted a German Shepard puppy. She found a couple of breeders a few hours away, and was leaning toward a $1800 puppy. I went on CL, found a litter locally, and she picked out a terrific puppy (now a wonderful dog) for $275. She wanted a nice gun cabinet like her Dad had when she was a kid. Took me a bit to find one on CL, but it had been listed 29 days earlier. Seller still had it. Twelve years old, never had a gun in it, bought it for her ex and it was in the way. Matched our office furniture well, so I took the wife and we went to see it. Lots of dust, so the wife starts wiping it down to check the finish. She opens a drawer, looks in, and closes it back up. Sticker inside said "Ethan Allen". Bought it for $125 cash, and later priced a new one, $2200. Didn't matter, the seller wanted it gone and that's what the market would bear. I've bought lots of metal at pennies on the dollar the same way, and passed up THOUSANDS of items (especially tools) that were priced higher than new.
Knowledge is king, both buying and selling. Either way, I want to be fair.