The current Ethereum price movement is at $2.5k. It seems that with a capital of only $100, of course for me, that is very little because, at least for the profits obtained to have quite a lot of value, you need at least $500 in capital. But if the capital is a little like that, if it is used for learning, then that is enough.
As of the time of the thread, which was September 2018, if the Op bought Ethereum for $100 back then, the price of Ethereum was 283.50. As of that time, fast forward to today's price, and Eth would have been worth more as the $100 could have given him 0.35 ETH, which if calculated with the current price, which is $2,540 (as of the time of this comment), would be worth $880, which is a lot for him. At least it's a decent profit.
That's if the Op didn't sell before now since many are not patient enough to be holding down coins for a long period of time, especially when it's a small amount and the profit won't be worth much; if it was something up to 1eth, it would have been worth the waiting.