Chuckit Kick Fetch Toy Ball for Dogs [Orange/Blue, Small] - Add-on item - $9.47
Chuckit Fumble Fetch Toy for Dogs [Orange/Blue] - Add-on item is also $9.47:
The small max glow is also on sale for $11.47 (non add-on item):
The diameter of this ball is 5.8" which is plenty big enough for my 42lbs mutt. The grooves in the ball make it easy for my dog to grasp in his mouth even though it's somewhat big. My dog destroyed all of this toys pretty easily but this ball has held up pretty well for 7 months now while playing fetch 1-3 times per day for about 30 minutes each time. However, we only use it for playing fetch outside so I keep a watchful eye on our pup so he can't destroy it quite as easily. YMMV as an inside chew toy. I bought another one to replace his current one when the time comes.
BTW - I paid $9.79 for my first one but it's been hoovering around $16-$20 since then so this seems like a pretty good price. Yes I realize it's still expensive for a dog toy but it's well worth it IMHO.