Do a search on the forum for NcStar, BSA, Barska, Leapers, etc. and you'll pretty much see the same discussions.
They work for a few people, usually on small caliber rifles or handguns (i.e. 22lr). I have a cheap WallyWorld Tasco red dot on my Ruger MK II and it works fine, but I wouldn't trust it on much else.
Chinese scopes are pretty bad for most people. They don't hold zero (as I discovered with my Mosin back before I sold it).
Since you are wanting to mount this on a 30-30, you really should get a better scope. There are good scopes out there that won't cost you an arm and a leg.
As has been said before, "buy once, cry once."
If you're planning to do any hunting with it, then please, for the animal's sake, get a good scope. Something made in America, Japan, parts of Europe.
If you're just target shooting, well it's your money and the worst that will happen is you eBay the scope for half what you paid and have to buy a good scope.