A mate at my club is fully sponsored by Kookaburra (Plays Australia U19's, so no surpirses there), and his bats are a much different shape to the ones off the shelf and they feel fantastic and perform bloody brilliantly, and I would easily pay more than £250. Mind you I'm in Australia, so top range bats over here would cost £350 - £500 over there.
Like Buzz said though, pick it up, have a swing with it, then tap it up. If you like it, try and work out a price you and he are comfortable with, if not then just move on. Don't buy it because it's a 'pro bat' as you will end up regretting it if it isn't suited to you.