For me it started in 2012 when I wanted a fun toy to use over the weekend. Nothing actually came of it because I just didn't know enough about batteries and motors yet, but I did do some research. I'm been much more electrically inclined throughout my life, so I know I didn't want to go the gas route.
Back in 2013, I decided I was just gonna go for it and build a bike. This time I actually did have something I wanted to use it for. I wanted it to commute to my fast food job at the time in high school.
Now it's 2018, and I have constructed a new ebike which I now ride 16 miles every day to and from my College (U of M Dearborn). I now have a 2007 Chevy Impala I got from craigslist for $1000, but I rarely use it. My ebike is just a blast to ride, while my car seems quite boring in comparison. Yeah a car is faster, but you don't have the wind whipping in your hair, or the freedom to ride on both the sidewalk and the road.
Now I live in Michigan, and I have never seen another person riding an ebike in our state. There are probably people out there, but ebiking just isn't a thing here. Because of this, the laws for ebikes are quite flexible (because there aren't any dumb-asses to mess it up for the rest of us yet). The state of Michigan just recently passed some laws classifying ebikes of any power level to be ridden at least on the road legally. Ebikes under 750w can be ridden on trails now as well. Before this, they were classified as mopeds, so lawmakers didn't know what to make of them. Gas powered bikes require a license, registration and expensive car insurance. Glad I went the ebike route!
I now have an ebike with:
"36v 500w" (overvolted to 52v) yescomusa rear wheel hub motor $150 (now draws 1.1KW at 21A and goes 30mph on flat ground, waaaaay more fun than my 36v battery).
52v 20AH 14S10P ebike battery constructed from old drill batteries I collected at my local scrapyard for $50.
A 2008 gary fisher mountain bike from craigslist for $80.
There was some other stuff not worth mentioning like the battery bag (lunacycle triangle bag), bike speedometer, bell, tons of wires and duct tape that I didn't mention. But the total cost was $500 for everything. The bike has already paid for itself in gas savings.
How did you guys get started, and what system do you use now? It would be interesting to share.