If I bought $100 of Ethereum. Can I make money? Was it enough?
If you look at the current value of ETH, 100$ is very small,
Yes it's small, but if you will look at it, OP posted this thread on Sept 28, 2018, that time ETH is just $229 at the time of OP's posting. If he bought that time, he will get 0.436 ETH and looking at the ETH price now, OP will highly like get a $1.2k profit.
Calculations
$100 / 229 (previous ETH price) = 0.436 ETH
0.436 * 3024 (current ETH price) = $1318
So yeah, that was very profitable indeed.