How much does the MLB spend on baseballs in one season?

Well, they use about 110,000 to 115,000 a year.

Rawlings is the official supplier... Retail Price of Balls (Approx): About $10 Per Ball...

But, you see, I don't know if they pay more of less for the balls, considering the enormous cost of shipping that many balls, but they probably pay less than retail...