I use freebitco.in's interest program.

If you deposit 0.0003 Bitcoin minimum, you will earn 4.08% interest yearly, paid daily. So the more Bitcoin you deposit, the more you receive. I would advise you to stay away from their dice feature, which is very risky, you can also use their free bitcoin every hour feature, which pays up to 200$ of Bitcoins to your account every time you claim from the faucet.

Regards, excro