Interest and Gambling

Q: Is it permissible in Islam to participate in a campaign where I send $0.001 (a very small amount) to someone, and in return I receive a random reward that could be anywhere from a small amount up to $80? 

The reward is uncertain and based on luck. However, the money I send is never lost — I always receive a reward that is greater than the amount I sent. So I never lose my money, I only receive more. Is this considered gambling (maisir) or is it halal?”

Q: Is it permissible to have a two way bet with a friend where no money is involved. 

For example, if you lose you wear an outfit of the winners choosing or change your wallpaper that doesn't involve haraam to a wallpaper of their choosing etc.

Q: There is a cricket tournament called the SA20. In the SA20 tournament, if the batsman hits a 6, and someone from the crowd catches the ball with 1 hand, they win a share of 2 million rands. You do not have to enter any competition or anything, you just have to catch the ball with 1 hand and you win a share of 2 million rands with other individuals who caught the ball with one hand. 

Now I caught the ball with one hand and I'm entitled to the share. Now the sponsor of this competition is Betway. Is the money haraam even though I just won a competition without any money added to it and without taking pictures of the check with the name Betway. I just won a competition. Is the money haraam if it comes from that company?

Q: A filling station is running a competition. Anybody who fills more than R500 gets entry into a draw. No additional money is required to be paid. 

Is it permissible for me to fill at this filling station so I can be entered into the competition?