SWEET MATH  (you don't need to use all caps there)

A hockey stick and a ball cost $50. If the stick costs $49 more than the ball, what is the cost of the ball?   (don't put a space between the  "?"  and the last word in the sentence)

(the ball costs one dollar.)

Also, you asked "What is the cost of each";  You answered that question in the first clause of your statement.  "A hockey stick and ball cost $50."  You also state that the stick costs $49 more than the ball, so the only logical question left to ask is "What is the cost of the ball?"  

SWEET MATH

A hockey Stick and ball cost $50. If the Stick costs $49 more than the ball., what is the cost of each?

The ball is $0.50 and the hockey stick is $49.50. Unless of course $50.00 is a sale price only applicable when the two are bought together, in which case, only Chuck Norris could answer this question!