Just check coupons out (with price alert and history). What is best price?
30 Min endurance after electricity cut off, 2800 PA strong suction, Over 400 hour continuous working time
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest coupon code price check (UTC time):
Price history and price alert
Here is price history (for all/most countries) for Alfawise WS-960 Robot Window Cleaner.
Price records source(s): Gearbest
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)).