really i would say go for anything that is affordable! the price range usually with the used market doesn't often reflect the worth of the actual camera, but instead the amount the seller thinks its worth. if you're looking specifically for brands, Sony, Canon, Panasonic, and JVC are some pretty common names that i think are worth looking into. but beware! people can scam you online, and it's unfortunately a little hard to tell!!! often with these scam camcorders they look totally legit, and even mimic offical models sold! the main thing to look for is if you can find the model number on offical sites of the brand, just google the model number and then user manual, something should come up from the brand if its offical.
also!! media type is so important. if you're looking for easy, on, record, download, you're going to want a hard-drive based camcorder or a SD Card based camcorder. these are the easiest to use as everything in the camera is fully digital compared to other types like MiniDV camcorders! these use a also digital video type, but instead its recorded onto small video tapes (like a VHS Tape, but tiny). these can be digitized, but require more effort as it isn't going to be just drag and drop files.
personally, i have a Panasonic SDR-H40PC from 2006 (a hard-drive and SD Card based camcorder) and it works great! it has a great microphone, and has that old look to it but can record for hours on a card or the built-in hard drive.
happy searching!!