49
Step-by-step explanation:
 2 quarters
 1 quarter, 2 dimes, 1 nickel
 1 quarter, 1 dime, 3 nickels
 1 quarter, 5 nickels
 5 dimes
 4 dimes, 2 nickels
 3 dimes, 4 nickels
 2 dimes, 6 nickels
 1 dime, 8 nickels
 10 nickels
10 ways without pennies. Pennies can be substituted for any quarter, dime, or nickel, so ...
 8 ways to have 5 pennies
 7 ways to have 10 pennies
 6 ways to have 15 pennies
 5 ways to have 20 pennies
 4 ways to have 25 pennies
 3 ways to have 30 pennies
 2 ways to have 35 pennies
 2 ways to have 40 pennies
 1 way to have 45 pennies
 1 way to have 50 pennies
For an additional 39 ways with pennies.
There are a total of 10 +39 = 49 ways to make change for 50¢.