I don't remember the brand but I use a 30mm 1x red dot scope, it was 35 to 40$ range.
As far as ammo, you got choice from birdshot, flares, flashbangs, slugs, rubber projectiles, bean bags, buckshot, liquid filled bags, sabot, super expanding, door breaching, combos of slugs and buckshot, buckshot and birdshot combos, and many many more.
Shotguns are very versatile, and can be loads of fun. The 590 is a fine shotgun as are 500's.
Navin R. Johnson: "He hates these cans!!!! Stay away from the cans!!!!"