Xiaomi CosBeauty PerfectGlow Skin Revitalizing Device (Banggood, Aliexpress: The Host Weight: 130g, Charging time: 900mAH, Color: White, Adapter: Input AC 100-240v 50/60hz, Size: 175.4*43*53mm(host), Working frequency: 1Mhz, Key: 2 IN 1 Power/Gear Switch, Brand: COSBEAUTY XIAOMI Ecological Chain Brand, 7.4V (3-4 hours), Usage time: 12min, output 12V 1A, Power: 5W (the best price with coupon)).
Basically copy coupon, view price history or create e-mail price alert. Best price?
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):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($461.69): BG10OFFAFF
2. ($503.99): 7bcdf9
apply it 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/feV
Old coupons (from the oldest to the newest): 502C6B, vipupgrade8, ML15%Pro, BGHC20, bgshOOp10, bGhOnEy10, BGHB20, BgoFErTaSchInA10, BGSD52469, BgcLuBofErtA10, BGAFF10OFF, BGCuponation10
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Here is price history (for all/most countries) for Xiaomi CosBeauty PerfectGlow Skin Revitalizing Device. The lowest price was: $349.99.
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)).