Oclean S1 UVC Toothbrush Sanitizer (Banggood, Aliexpress: Built-in 1000mAh Li-ion battery, charge for 2.5h, use for 20 days. (the best price with coupon)).
Price history, coupons and price alert are available on this page. 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 and price update (UTC):
Banggood
Banggood warehouse is located in China. You can get coupon down below.
Link: Banggood product page
1. ($31.27): BGHealth06
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/feV
Old coupons (from the oldest to the newest): BGO1899, 13f142, BGCuponation10, BG22371, BG10OFFAFF, BGwhielabel, BG10OFFAFF1, BANGGOODSD
(these coupons are old, so probably won’t work)
Price history and price alert
Here is price history (for all/most countries) for Oclean S1 UVC Toothbrush Sanitizer. The lowest price was: $18.99.
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)).