If you are betting on sports, selecting the "draw no bet" option means that you will have your money returned if the game that you are betting on ends in a draw.
For instance, let's say that the odds for a game look like this:Bayern Munich, 1.85
Draw, 3.50
Borussia Dortmund, 4.40
If you did a traditional bet on Bayern Munich and the game ended in a draw, you would be out your bet.
However, let's say that you wanted to choose the "draw no bet" option. Those odds might look like this:
Draw No Bet
Bayern Munich, 1.45
Borussia Dortmund, 3.80
Now, these odds aren't as good, but you would not lose your bet if the game ended in a draw.
You are obviously pay a premium to use the "draw no bet" option.