No hesitation here:
1. Top Flite D2 Feel. 15 ball pack (9.99 at GG). .666 cents per ball.
2. Srixon AD333. 2 for 25.00 (at GG). 1.04 per ball.
Hx diablo tour
This ball has not been mentioned but I really like the NIKE Vapor Speed. It's a 3 piece ball with great distance and excellent spin. You can get these for less than $20. I read about 3 months ago that a woman golfer who plays the Japan LPGA or (whatever they call it) actually won a tournament using this ball.