New to poker means you dont know the pokerrules yet? Or do you mean new to online poker?
In the case of new to poker, get the hang of what are the best hands etc before you going to play.
If you know all of that, i would start with some $0.50 9 mans sng to see how it all works, etc. 3 will be in the money, so less variance. when you do good there try the 45 mans, after that 90, 180 mans. After that try mtt(or if you dont want mtt, then stick at the sng and rock there) and see if you can make it there.
With a $100 deposit I would stick to 2NL for cash games and SNG and MTT $1 or less. This a conservative buy-in that will avoid you from going broke easily unless you are just a bad player. If you go broke off $100 at these stakes you will want to re-evaluate your game.
If you have means to deposit more money then play whatever you feel like playing but most don't want to be depositing often.
9-max you will want to play tighter than 6-max. ABC strategy will work at the micro stakes but mixing up your game will be more profitable. Get a good poker tracking software so you know your opponents tendancies and gring as much as you can. Once you play 50K hands you will have a good idea about your skill level.
Start on lower limits(0,25/0,5 sngs), so that you can get used to the online aspect of the game, and then move on to higher stakes when you feel you can be profitable. Remember not to tilt, it's very important