i am terrible at making decisions - also, help neede buying bike
Okay, for maybe the past year I've been thinking about buying a bike and taking it on a very extended tour. Right now my basic plan is to save up money and tour across a continent. maybe europe, maybe america, not real sure right now. anyway, in pursuit of this goal i've been occasionally reading these boards and trying to do some research and figure out what exactly i want/need to buy. I've decided on getting a trek 520 since it seems to be a very solid bike, and also pretty much at the upper limit of what I can afford, considering all the other equipment i'm going to have to buy (panniers, camping equipment, everything). However, i don't have a local bike store that carries these bikes, and i don't have a car to get to a city that does. moreover, buying a used bike for significantly less would make this affordable, and buying new would most likely not. so i've been turning to ebay. However, once there I just can't decide if the bike is a good buy, and whether or not i should actually shell out my hard-earned cash for it. I have basically zero experience with bikes aside from riding them around as a kid and teenager before i was able to drive. so i don't know what to look for as far as whether the bike is in good condition or anything like that.
so, i suppose, what i'm asking you guys is, what on earth should i be looking for from these bikes? what would be good for the bike to have, what would be bad? are certain years better than others for a particular reason? any other suggestions? i just feel really lost on this one, none of my friends are into bikes at all, and it just feels like i'm a bit lost.