I've watched a few of those videos on how to convert a bike, there are 3 variations of chain drive and direct drive setups. If you want a relatively short range and a chain drive rig where you lose half your gears on a mountain bike you can get by with a few hundred dollars.
The direct drive setups can get up to around $900 or so for a high quality kit with good batteries.
I toyed with the idea but I'd be more interested in the build than the actual use.
Last edited by KFWA; 10/20/21.