Investing in the market and his altcoins, you need to make smart moves in the market if you want to obtain some good profit, $100 can be a good quantity to invest in exchanges like Bittrex and Polo, and some cases C-CEX or Cryptopia.
Cheers!
Yeah with that amount you need to have a very good decision because it is not easy to do that amount in investment. Just be wise in every decision that you are going to do.