Anything but gambling I guess!

You can earn money with money then convert money to
BTC 
I think gambling is not the best way to earn money because gambling its not good. You must claim faucet or joined a signature campaign to earn free bitcoin no need to invest just you have to do is apply a sig campaign and make a post so its very simple to earn bitcoin.
Gambling is no way to earn money, it's a way to lose it.
Of coures somebody hits a big pot every now and then, but on the long run the house will always win.
And that means the customers lose.
I don't consider my winnings in gambling as earning..All of your winnings would just return to the house after...Better use faucets, signature campaign, data entry or those that asks you to sign up and earn a little than trying gambling and lose all of your penny in it...