well.
1. buying a mosin because it's a mosin is like buying a kia because it's a kia.
2. yes, every world war 2 collection must start somewhere and the cheaper rifles will give you an appreciation for the more expensive ones you buy down the road.
3. maybe but with a lot of caveats.
most mosin nagants, especially the junky WWII production izzys(I've own 2 myself and still own the nicer of the pair) suffer from several problems the most common and most extreme being accuracy. these guns were cranked out in the millions in a short amount of time with nothing even loosely resembling quality control. the russians wanted a pike that could shoot bullets and as long as it performed both functions they were happy. in addition, russian conscripts did not receive proper training in weapons maintenance, so they shot a lot of corrosive ammo and didn't properly clean it, and when given the provided steel cleaning rods they gouged the muzzles into clover leafs. as a result most of those 1940-1944 izzys shoot 4 MOA at best. that's all well and good if you intend to only shoot from sandbags at non moving targets at distances no greater than 100 yards but for moving targets that have a 6 inch humane kill zone, that does not leave you a lot of margin for error.
another issue that they suffer from is mostly just inherent to the mosin nagant design itself and that is slow follow up shots, if you intend to hunt, you better be willing to pass up any shot that doesn't offer a sure chance of a one shot drop(which is almost an oxymoron when it comes to elk hunting). another issue, the safety sucks, if you intend to hunt with the mosin, taking the safety off is A) difficult especially while wearing gloves and B) dangerous( risk of accidental discharge). your only real options are to either pack with no safety and deal with the consequences or carry in condition 3 which is a huge pain for hunting and often leads to a lot of missed chances.
lastly, I like PRVI as a source of good brass and decently accurate plinking ammo, but I don't trust the quality of their bullets for hunting. I lost a lot of deer while hunting with prvi softpoints in a 243. I'm sure their x54R stuff is more than potent enough for deer but I would never trust it on elk. if you intend to hunt with it, I suggest winchester 180 grains or lapua 185gr ammo(but that lapua stuff is expensive as hell). personally I would prefer working up a handload with a good bonded or guilded metal bullet myself.
so there's the caveats, your rifle needs to be more accurate than the average, you have to accept certain risks, be willing to pass up certain shots, and use ammo way more expensive than most people want to put in a mosin nagant, but if you meet all those criteria I say go for it, hunting with old guns is fun, exhibit A