first off 100$ is a limited budget for any kind of IM endeavor but you might be able to pull something off in the long run...
You shouldn't invest it in anything, that's how low of a budget you've got.
Do some CPA's with free bloggers/wpress blogs. It will take you a while to earn some dough but if you do it on a massive scale you could start getting 100$/day in ~ 1/2 months after the initial setup.
After my first month of CPA I was at 70$/day with all the shaving from AWM and after expenses (yt accounts/views/video ratings, etc)
I'm suggesting you get into CPA just because it's pretty much a one time setup that you need to take care of... nothing new to learn each day, no giant mountains to be conquered. This leaves you with time to think about other projects and also has the power to bring in the money you need for those projects.