[BroadHopper]

Do what is comfortable for you. When selling a boat, I advertised on Craigslist and Boattrader.com. I also buy from various sites. If need be you can ask a marina to broker your boats.
Last boat I sold was on Craigslist. The Liberator was listed on Thursday sold on Saturday to a guy from Cape Cod. I bought a boat on EBay. Half the NADAGuide price. The Formula was auctioned off by a Maryland marina when the owner failed to pay 7 years of storage fees. Stored indoors, it just needs a general cleaning, replace gas, that's it. I drove down and hauled it back here.

NADAGuides will give you a fairly decent starting point on the value of boats. Almost always the boat sells for a higher price so do some online research on selling price.

Always have your new boat surveyed, especially when buying from a distance. Always buy a boat used only in fresh water. Saltwater boats tend to have problems although some folks beg to differ.