Coupon currently available – price is $124.99 (from Banggood). Flipsky Waterproof Brushless DC 6374 Motor 140KV 3600W for Surfing Boat Underwater Thruster Hydro Efoil RC Boats Vehicles Models Parts.
Updated:
Banggood
Warehouse in China.
Link: Flipsky Waterproof Brushless DC 6374 Motor 140KV 3600W
Price: $124.99
Additional Banggood coupons:
1. First page
2. Second page
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Price history (for all/most countries) for Flipsky Waterproof Brushless DC 6374 Motor 140KV 3600W is here. The lowest price was: $124.99.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).