$150 for an SKS, for fighting, taking deer-sized game to 150 yds. Practice ammo is 8c a shot, and the 150gr, 2400 fps CorBon softpoint makes it really effective, indeed. A $40 trigger job isa big help,with this gun. You can scope it pretty well,for under $100,if you want more precision in your hunting shots, or want to hit camoed, cover-using men, at more than 100 yds.
$50 used Glenfield M60 Marlin 22 auto rifle, for small game, altho the $100,used 1022 Ruger is quite preferable. $50 trigger job really helps the Ruger, is basically "undoable" on the Marlin. $30 should suffice to adequately scope either one. You might even get one for that price that's already scoped,if you look around, for a private party sale.
$50 Mosin Nagant, for the really big game, 7.62x54 is essentially a 3006, and the practice ammo is very cheap. Use good, US made softpoints for hunting, tho. Do a trigger job on it, fit a decent scope,and it'svery capable to 300yds on deer, 400 yds on elk and Grizzly.
$150 used New England Arms single shot 223, with a smithed trigger pull (explanation of how to do same is elsewhere on this site) can easily handle 200 yd crows and prairie dogs, or 300 yd chucks, coyotes, foxes, bobcats, nutria. Scoping it is less than $100,if you go at it right. Trigger job's about $60.
$50, used 3" chamber 20 ga single shot will handle shotgun chores. Put some lead shot in the forend and buttstock, upping the weight by 1.5-2 lbs, and add a good recoil pad. You will NEED it, for the 3" mags,on waterfowl. A $40 trigger job is helpful, too.
So,if you want to maximize these 5 guns' utility, you spend about as much on glass and smithing as upon the guns,but the smithing is simple, most guys can do it themselves. You dont HAVE to have the scopes, but they are a big help.