the shotgun will do more than hunt deer and be about as accurate with slugs as a SKS would be, you will just be limited to what ever range the slugs group well out to(say a 100 yards or less )
so I would NOT recommend the SKS for hunting period,
next suggestion might be to look for a used rifle, like a savage bolt action, they can be found all over the USA pretty darn cheap and be more accurate than both your suggestions, IF that is DEER is the more likely thing you will be hunting!, it will be useless for anything that fly's and be dangerous to shoot at anything that fly's with it as well
have to ask yourself what do you plan to really hunt , same cane be said about USED shotguns, I would also tell you to consider a rem 870 shotgun, as like the mossberg they can be had cheap and you can also get a good slug barrel for it to make it better for deer use(I highly recommend using a slug barrel on any shotgun you plan to shoot slugs with, or at least MAKE sure it has a am Improved cylinder on it so slugs can fly without issue's, as you do NOT want to be shooting slugs out of modified or full or tighter choke on a shotgun barrel)