Have a look at megamine.com - they offer a 1yr contract for 1Thash (including hosting and power) at $4,200.
This is a lot cheaper than CEX.io
CEX.IO for comparison is 7.39 BTC (approx.$4,700) + $260 a month , so a total annual cost of $7,800
1THs at PBMining is ~$2665 at the current exchange rate. And zero fees per month.