Idiom about choosing things
How about hold out on? From M-W:
hold out on: to withhold something from
Your example: In providing your second best basketball rather than your really nice basketball, you were holding out on your friends. What would your friends say if they were to find out you had a much better basketball: "Wow, we can't believe you were holding out on us." Or "Why were your holding out on us? Let's play with the good ball."