I agree with Buzz, people get way caught up in expensive bats when teaching the proper swing for 20 minutes will do far more than any bat will ever do. Buy a decent bat, but don't spend $175 on an 11 year old.
having said that, bat technology these days is pretty insanse, you can spend $300+ on a softball bat, and there is a cottage industry of guys who will take a banned softball bat and convert it so that it appears to be a legit bat.