5.2Ah Li-ion battery, 187Wh, 25km mileage, 45km with expansion battery, Maximum Speed: 20km/h, Max Payload: 100kg.
Just check coupons out (with price alert and history). Let’s see what best price is ATM.
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 code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($529.21): BGEBSC15
2. ($553.99): 7bcdf9
apply code in your basket (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): PICODICOM, c40a7e, d300f6, BGES1KOD, BGNBES1CN19, 5d1752, BGNBES1CN11, BGNBES1CNB5, bGpAnDacHeCk, BGNBES1CN, issames1cn, BGSS20SW, BGAFF7OFF
(probably won’t work, but you can try them out)
Price history and price alert
Check out price history chart (for all/most countries) for Ninebot ES1 Electric Scooter. The lowest price was: $289.99.
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)).