Most any entry-level ball will work, you could even go up to some of the mid-priced balls without running into trouble.
The Brunswick's Power Groove, Storm's Tropicals, Roto-grip's Planet line, Ebonite's Element line all have excellent balls for a modest price. The Planets and Elements have several choices of covers while the Grooves and Tropicals are pretty much reactive pearls, but they're all fine balls, you won't go wrong with any of them.
Personally, the Roto-grips are very appealing to me.
SH