Just check coupons out (with price alert and history). You probably want to know what is the best price?
5 Brush Modes Essence Sonic, 5 Brush Mode (Clean, Sensitive Care, Soft Massage, White, Polish), Vibration Frequency 31000+ Per Minute, IPX7
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.
Link: Banggood product page
1. ($26.00): BGHome15%
2. ($27.53): BGAFF10OFF
3. ($27.53): bGhOnEy10
4. ($27.53): BGdragonBoat
coupon code has to be applied in shop’s cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): DGYS1129, CP1205, 99ce41, code1573, CODE1573, 502C6B, vipupgrade8, ce2ca1, TTxBG10, BGYS21, BGDigoo15%, BGPYS1155, AFfbG10, BGDG1119, BGDGR189, BGBGHFRI15, BGIHNQ, BG030301cyy, BG22iMars, BGDG15, BGIYS11, 20%DG422, BGSS10%SW, BGDGASG, BGCuponation10, 13f142, BGHONEY2110
(you can check these old coupons out, but these probably won’t work)
Other warehouses/versions
This item is available in 2 another warehouse/versions!
1. China – Digoo DG-YS11 Sonic Toothbrush White ($-3)
2. Europe – Digoo DG-YS11 Sonic Toothbrush White [EU] ($-3)
Price history and price alert
Do you need price history chart (for all/most countries) for Digoo DG-YS11 Sonic Toothbrush Black? 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)).