my mate bought a BRAND NEW chinese bike (offroader) 125 for £550.
he beat the C**P out of it offroad for a year, fell off, didnt run it in, didnt service it, replaced fallen off/broken bits with ebay specials and the thing never missed a beat!

he then sold it for £400 !

it is probably dead by now, but it was good whilst it lasted and a whole years offroading for £150 is a dam good result!!!......