IBOOK info?

I really want a white apple ibook. I will use it mainly for entertainment purposes. I notice, on ebay, there are a ton of them. I'm totally MAC illiterate. What should i look for. How many mb's or gig's? I know i do want wifi? All the headings seem the same but i notice that some are going for a lot higher bids than others. I dont want to buy a lemon, so what should i look for? Mainly fun, not for business. Games, itunes,stuff like that is what i would use it for.