From experience even at a younger age (certainly not 7 yo...maybe 9) the high performance bats perform better. it's just not for show. My 9 year olds 2008 Synergy clearly has more pop and a larger sweet spot than the $20 Easton. I got a deal at $149 on a 30/20 and figured I could sell it for $70 when she moves up to the next bat so really I am only out $80 bucks for a much better bat she'll use 2 seasons. That is only net $40 per season. That being said, any bat the feels good and makes solid contact on the sweet spot with a decent swing path should get you the results you are looking for.
