Welcome to the crypto curse sir!
If you're into buying and holding BTC is a good bet.
If you're into trading forex, indexes and crypto on a CFD basis check out primexbtc.
I heard about BTC when it was like $3 USD and thought my friend was crazy.. lol
Started revolving my life around it at about $100 USD. Started teaching myself how to code to get it.
If you're looking for a place to invest your STEEM I suggest Steem-roller.com which is a place I run that allows STEEM invsting or 1% house edge dice.. With up to 99x investment leverage.. So you can invest like 1 STEEM and have it function as 99 STEEM in the bankroll.
Got my first 0.01 BTC from a giveaway on the forums at bitcointalk.org if I recall.. Can;t truly remember.. It's been a long time now.
RE: Just invested my first $100