I agree, "we know this already" as other have stated may be true, but not for everyone.

I have a friend that have seen and tested my folder. She have several full size bikes, old and new. She decided last fall that a folder would be nice, but she wanted it cheap.. So she started looking at the local "Craiglist" and soon asked me if it was ok to buy a bike similar (looking exactely the same) as the cheap bike. One seller asked approx £120,- one asking £180,- .Both the bikes were new. She was convinced that the cheapest bikes were a bargain. I managed to talk her out of it. Two weeks later a Dahon mu p8 was offered. Seller said he bought it for his daughter and she rode it maybe 50 kilometers and then parked it. He asked £170,. My friend lost interest and wanted to wait for a cheaper bike.

This article may not be for you but there are peopel out there that know absolutely nothing about bikes and can not judge the quality of anything mechanical. I am going to post a link to this article to my friend and hope it helps her judging. I know she trust my judgement but also I suspect she think it is possible to find a fair bike cheaper than that.