250W motor, max 25km/h speed, max 25 degree gradient, 7.8Ah Li-ion battery, 16 inch inflatable rubber tire for different grounds, max 30 – 40km mileage with pure electric mode and 60 – 80km mileage with moped mode, Charge time: 5 hours.
Just check coupons out (with price alert and history). Best price?
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.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($499.99): BGFDD2CN
2. ($641.00): 7bcdf9
apply it in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): issamfiid2, PICODICOM, 5dd9c0, 6d9494, itfiidod2, BGFD201, BGFDD2CN19, BGFDD2CN11, BGFDD2CNB5, bGpAnDacHeCk, 2880c7
(these coupons are old, so probably won’t work)
Price history and price alert
Check out price history chart (for all/most countries) for FIIDO D2 Electric Bike Gray 7.8Ah. The lowest price was: $429.99.
Price records source(s): Gearbest, 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)).