If I'm not mistaken, u r talking about the hashie.co offer. But, their 10GHs is not completely free. U need to buy 10GHs to withdraw the mining profit from the free 10GHs.
PB Mining was offering a better deal a few days back without any hidden rule.
Currently
www.cloudmining.website offer is the best. They are offering 0.001 BTC/GHs.