My girls absolutely destroy tennis balls, if your little guy is the same you might want to consider Chukkit branded ones. Tennis balls last my goldens seconds, these have lasted a year so far!
I sound like some kind of ad bot, but I used to spend so much money on tennis balls that I couldn't help myself :D
My sisters one would steal balls from other dogs and spend hours evading you in the park to avoid giving it back. He grew out of it eventually and is generally a lovely boy.