Definitely agree with the Baum Bat recommendation. But I have seen some tourneys that won't allow them. Look for rules notes that disallow "composite" bats. I think PG's WWBA tourneys are among those that don't permit them. Sometimes it goes undetected, but you may need to have at least one other bat at the ready.
I also recommend buying one of the cheapest wood bats you can find, then taping the barrel, so that you have something to use in BP, especially if you like to use mechanized batting cages with those hard rubber balls. You can even use a cracked bat if you use glue, a tack and some tape. This gets the player acclimated to the different weight and feel of a wood bat, without putting your expensive purchase at risk just for practice. Use white tape on the barrel, as this has the added benefit of letting you see where contact is being made and whether it is or isn't on the sweet spot.