As long as you win or lose till you have original bet, you can play and if this is not happening, cut the losses and leave. If you win for the first time you have played, play again and leave the original bet to take that one home. If you have made up your mind to play for some time than you can start with three or five dollars but that I will not suggest as losing a $3 on the very first bet will not be good for you.
You can invest a dollar to get yourself started. As there are 50% chances of occurring of both the color (minus the 0). We are always in dilemma which color to choose. There is no surety that you are going to win in roulette but you can soar up your chances of applying proper strategies.
