You can create price alert here, copy coupons and view price history. What is the best price?
Voltage: 100-240V, Main Engine Speed: 100000±10%rpm, Charging Time: 4.5h, Power: 120W, Color: White, Noise: about 80dB, Brand: SWDK, Model: K11
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 and price update (UTC):
Banggood
Banggood warehouse is located in China. There is one great coupon!
Link: Banggood product page
1. ($146.99): 7bcdf9
apply code in your basket (cart) after clicking “Proceed to checkout”. Click to copy code and open shop.
Old coupons (from the oldest to the newest): BGSWDKK, BGAFF7OFF, bgshOOp10, BGHome15%, BGHOMEAPP13, BGHOMEA13
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Do you need price history chart (for all/most countries) for Xiaomi SWDK K11 120W Vacuum Cleaner? There we go.
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)).