zactly, i found a mosin nagant rifle for about $135. here's the thing: those don't break. i mean short of running it over in a dump truck or something. if you can pick one up and find a bayonet, even if you run out of ammo, those are sturdy pieces of hardware, and the bayonet is like as long as your arm. the mossberg maverick 88 is a little over $100, shotguns are one of the most useful and versatile weapons know to man, just because in call of duty, the shotgun won't do anything past 20 feet doesn't make it true. buckshot can reach out and touch someone, and if you have a rifled slug you can really put a hurting on someone at range. even if you don't kill them at rang with buckshot, they'll go away, it's true. no one likes to be shot, by anything.
if, however, you have the scratch to pick up a mad decent gun, i would suggest the Kel-Tec KSG shotgun. it's the first ever bullpup design shotgun with twin 7-round feedtubes for a total of 14 rounds. the unique design means you can have slugs and buckshot loaded and switch between the two with the flick of a lever. there is so much awesome packed into this shotgun that the first time i saw it i had to change my shorts (crap a brick or jizz in my pants, i'll let you decide which). if shotguns aren't your speed, if you prefer an AR platform but fear that it may be cost prohibitive to buy one, fear no more: the Del-Ton DTI-4 rifle is here. cheap, economical, and still one of the best AR platforms on the market. a little bare bones, but what do you want for $750 (cheap is a relative term). wanna take that barebones AR from just plain awesome to complete bad-assery? check out combat sport supply. here you can find good quality accessories for your gun (once you've bought one) for a good price. you can also find tactical gear, so... fun. well, that's all i have.