Being from Canada, like me, another place you might check out is Biktrix in Saskatoon. I see Roshan has the BBS02 listed at $788.00Cdn. Not sure about taxes/shipping.

Bafang BBS02 500W-750W Motor Kit ? Biktrix

Maybe if you got 2, you could even get a better price?

I have purchased from them in the past and their service is excellent!