Is there any other way to earn bitcoins besides from mining?and joining campaign as well?
If you like to earn from scratch or without any investment, I guess the only way that you can earn is by selling your services.
Think what skills you have and you can find many services here that pays good.
But if you are a risk taker and would like to earn in the fastest way, you can try your luck in gambling and also in forex but you need to understand what forex is before taking rest to avoid losing all your money in a short period of time. Goodluck.