RE: how much would U spend on a used liberty?
if you can't get him down to between $350 and $400 just watch e-bay for a few days and you'll find one in that price range. Try archerytalk.com classifieds too.
Sure, in good condition its probably worth more than $350, BUT unless he sells the bow to somebody who doesn't know any better he's not going to get 5 for it when everyone else is getting 4 for theirs.