The ball size depends on the player's age and sex.
Baby basketball: size 1 to 3.
Girls and boys under 10: size 5.
Girls aged 10 and up, women, and boys aged 10 to 12: size 6.
Boys over 12 and men: size 7.
If you want a very durable ball, go for a rubber ball. If you want a ball with a good feel, leather or synthetic are the right materials.