Dont believe everything you read... Do your research, and dont trust BitcoinX calculator OR genesisblock calculator, but rather an averaged weight of the two.

I would not buy this miner... look around...ask around.  Best bets are KnCMiner or Bitfury, Cointerra...possibly Hashfast.

Make sure they take a Credit Card or Paypal so that you are protecting yourself!!!

I would also ask them who's chips they are using... it will be Avalon or possibly BFL.