I think Freebitco.in has 5% House Edge. Please correct me if I am wrong.
Yes, the house edge is 5%.
The House edge can be calculated using the following formula.
HE = 1 - ( multiplier * profitability of winning )
HE = 1 - (2* 0.475) = 0.05
It should mentioned that if you consider free lottery tickets, free golden tickets, free spins, reward points, daily jackpot and monthly contest, the house edge is lower than 5%.