There are endless choices for Good brands for rifles and shotguns.
Shotguns: Mossberg, Remington, Bennelli. Pick one in your budget and shoot away.
Rifles: You will have to be more specific in this case. There are multiple platforms to choose from like semi-auto, bolt-action, carbines, AR15's, AK's, piston, DI, etc etc.
If you are choosing between the 2, the shotgun is the more sensible choice. You can buy a brand new Mossberg 500 shotgun for $299. It will serve multiple uses of home defense, cheap shooting, and even hunting. 25rounds of birdshot is $6 at Walmart.