My fatbike motor is a 500W geared Bafang, similar to what was going on the Sondors that year, that I bought in 2015 from Cnebikes in China for eIther $340 or $430, I don't remember the price, but it came laced in to a 26" 4" rim, with controller, display, ie., a complete motor kit to fit a 175mm dropout frame. I don't see anyone in the US selling a similar product right now on ebay. I see bare motors for $250-300.