Just found a great deal from HashProfit:
Mine Bitcoin for FREE for the next 7 days!You get 200,000 KHS (will earn approx $0.57/day) for 7 days plus a 10,000 welcome bonus. You also have the option to buy more KHS at a 35% discount today.
https://hashprofit.com *removed referral*
Checked it out:
Your hashrate 200 Kh/s
Earnings with your hashrate 0.00140 BTC per day
or 0.56 USD per day
7 days = 0.00945 BTC = 3.80 USD
Can't withdraw at the end of the trial, unless you invest into hashpower.
Minimum you can buy is 15 Kh/s which is about 9.16 USD , that 15 Kh/s ROI's in about 7 month (~ 206 days) according to them.
So, invest 9.16 USD so you can withdraw your "free" 3.80 USD ...
I dunno, this doesn't look like it makes a lot of money ... ROI of 7 months, slighty quicker if you invest some serious money.