I've been helping the friend to choose the bike the other day and we went to specific bike open air market. As I remembered the normal price for entry level bikes was ~400 EUR, but the Chinese mountain bikes there were priced something like ~100 EUR for the new one. For new one I mean it was right from the box with some branded parts from "Shimano" (probably fake :)). I've took a ride of one of the bikes and it seemed OK, without any sounds or discomfort. What is really the big difference? May be it's worth to buy 4-10 cheap bikes instead 1 expensive one for 1000 EUR? I mean, yes, the parts will be of cheap quality, but when they are worn - I probably can even install the original ones in the future or am I mistaken?
Example: http://trinx.ge/index.php?m=126 The majority is priced ~150$.