[PimpS]

Lars!
All i can give you as an advice is to take with you some friend/mechanic who knows his job and bikes in overall. I was very pleased with buying bike advices here. I went with my girlfriend, who knows some tricks when buying used bike. Seeing mine, we were convinced that we bought the right one, with the right price. Friend mechanic who gave my bike some tlc, said at first glance that the bike is good and was well kept (it is about 12 years old after all...). Today it serves me well, i know i will have to change the chain at the end of season, but that's it.
So, go cheap, but don't go to cheap too. It also depends of the accessories the bike has, if has any. Mine has accessories which i would pay at least 400 dollars for them (custom made saddle bags, roll bar, sissy bar, luggage rack)... i also had to buy tires, maybe you, won't need them new (it's about 200 dollars cost)...

Buy good, ride well and safe!