Let's say that you have a fair coin, and someone offers to pay you a fixed amount for every time the coin shows heads, and you will lose the same amount if the coin shows tails.
Once you have the coin, you're allowed to toss it as many times as you want. When you stop, the amount you receive or owe is determined based on the difference between the number of heads and tails.
My first question is, is this game rigged against you, or does it favor you, or is it a fair game? Next, Is this game profitable, as in, are you guaranteed to make money?
Now, let's say the other party adds a condition that you must stop on a tails. Is the game still profitable?