wesnewell said:
I wouldn't spend more than $700 for everything, including a new bike.
That's why you'll never know better than what you have-- a toy bike meant to be a rarely-used Christmas present for an adolescent, with a toy airplane battery that needs its own fire cabinet.
A real bike that's built to last and perform decently at higher than normal loads and/or speeds costs significantly more than that all by itself. $700 will buy you a reasonably OK bike for average pedal-only use. A safe and reliable e-bike battery with charger costs $400ish and up as far as I can tell.
A hub motor kit is something you can cheap out on, but reserve at least $100 extra for a new rim, spokes, and competent assembly. The stuff that comes laced to the hub will pretty much always be trouble-prone junk.