Someone might have asked this before, but I am wondering this:
Why is the house edge 2% if I want to make a bet of 0.06 @ x2 ?
If I bet 0.15 @x2 the house edge is 3% Why is that?

SafeDice is using a variable house edge. By default, the house edge is 1% with a max win of 0.5% of the bankroll. Players can also have a higher max win with a bigger house edge, for instance, under a house edge of 2% there will be a max win of 1% of the bankroll.