Price history, coupons and price alert are available on this page. Best price?
Rated Pressure: 0.75mpa, Certification: FCC CE ROHS, Size: 240x 250x 365mm, Rated Power: 1500W, Heating Mode: Single Pipe Heating, Capacity: 6L, Max Heating Temperature: 65℃, Waterproof Grade: IPX4, Color: White, Energy Efficiency Rate: Level 2, Inner Container Material: Enamel
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($82.40): BGBK15
2. ($82.40): BGSMOFF
just apply this code in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGBAK15, bGhOnEy10, BGSM15
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Check out price history chart (for all/most countries) for Xiaomi Yunmi 1500W 6L Tank Electric Water Heater.
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)).