Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. I am tired of searching coupons, but I found one for you…
Link: Banggood product page
Coupon (69.63 USD): BG10OFFAFF1
(CouponsFromChina.com tip: 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
Old coupons (from the oldest to the newest): BGHONEY10, BGXPDE2908, BgcLuBofErtA10, BGHBHJ104, BGBTJUQ8, BGAFF10OFF, BGCuponation10, BGSCASV2, 13f142, BGAP0907, BGHONEY2110, BG10OFFAFF, BGSCAV2, BGwhielabel, BGJUN223
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Price history (for all/most countries) for SOOCAS V2 Sonic Toothbrush is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).