I would tell you to get what you can afford and want...but I have a few SKS' s and they can be decent rifles. You have to read up on them and make sure you are buying one of the more reputable manufacured ones. I have a couple Chinese..one ios ok and the other is pretty bad. I have a Russian that looks like hell but shoots like a dream....and I have a Hungarian model that ios good.
they are easy to shoot and load...but require a little work to do a THOROUGH cleaning (the gas piston can get pretty snarled up with crud when shooting the cheaper corrosive ammo)
The SKS is going to be the most affordable of the 2 you mentioned. The M1 carbines are blast but don' t offer much poke and they are fairly pricey to get a decent one.