well if your after a 20" mod bike - the best bike to start with is an onza t-pro
if your after a 26" stock bike - the best bike to start with is an onza t-rex spec 2 if you can, spec 1 if not
in reply to gasgaspunkuk, you could probablyi pick up a decent onza t-pro (20")with maggies for pretty cheap, they're often on ebay, if you can't find one there keep checking www.trials-forum.co.ukfor one, in the forsale and wanted section.
NOTE: there is a validation system so you can't post in the forsale and wanted section, but if you find a bike you want, add them to msn
nath