Chances it's a scam....zero.
Chances of actually getting one using that system....VERY SLIM.
Average time frame to pull it off if ever......8 mos to a 1 1/2 years at the soonest.
Chances of your $300 making some one else a rich S.O.B.....EXCELLENT.
Reason there are a million Ebay auctions on it........plenty of suckers w/ $300 burning a hole in their pocket.
Don't be one of them.