What you need
Trap Shooting you really only need a few things. First you need a gun. A shotgun to be specific. Most people use a 12 gauge. I use a Browning 1999 BT-99 Trap edition. Second you need ammunition. It can get pretty pricey but it is well worth it. Third you need a thrower. They are easy to find. They can be thrown by hand or by a machine. To go with the thrower you need blue rock.
The sport started because of hunting. While hunting a bird would fly up and the hunter would attempt to shoot it out of the air. Then for practice hunters would cage up birds then release them. People started betting on it. I'll hit more than you will and so on and so more. Then animal rights kicked in they had to replace the birds with glass jars filled with hay or powder. It was a huge hit. More people started doing it. They then had Problems with the glass o the ground so the switched to clay discs.