Im not sure if there is a minimum one needs to invest if pursuing that path. But i was thinking of sticking to my ZEC mine and drop 100$ into buying ETH every two weeks.
Current ZEC price now around $470 based on CMC stats. Feb 7, that was the very low price of this ZEC reach the bottom $300 and now price going increasing fast only took 1 week it has reach $500. So, i think it's very worth to invest on, it's good speculation to buying on every two weeks will get your good return profit in few month later.
Thanks all for the replies, and all comments are duly noted. I just wanted to touch upon you mentioning ZEC. Ive read multiple sources saying zec might not take of and stuff is still being worked out on it. But i have others saying when it does take off it will get huge. Which led me to go with ETH and it seems like a low risk investment. Might not pay huge. But im willing to take a risk with ZEC as i see its been on the rise and i am very curious to see how it will do this year