For home defense, unless your situation is quite unusual, a decent shotgun is a good start. 12 or 20 gauge depending on who's going to be shooting it. A Mossberg 500 or a Remington 870 can be had for right around $200-250.
For a rifle, same "it depends." If it's to put meat on the table a .308 or .30-06 is a classic hunting rifle. A .270 or a 7x57 is an easy-shooting alternative if the ladies are going to play. For self-protection you can caliber down to a .223 - a Ruger 10-22 is a low-cost option there. You're not going to be popping commies at 500 yds with it but then you aren't anyway, so why fantasize? An SKS is another way to go there.
These would be my suggestions for long arms at a bargain price. For a hand gun you'd find it hard to beat a .357 magnum wheelgun - they also shoot .38 special, a much lighter-recoil round, for practice. Semiautos tend to be a bit more pricey. It is especially important that you try a handgun first, though - it's a very personal taste.
More later - I think you'll find the forum full of good advice...
12 Ga. number 2 buck shot backed up with slugs.
I had a browning bar 12ga when I was a kid or should I say dad had one he let me use.
Sound advice there on all those.