Aliexpress
Click here… to search for KALOAD Smart Back Posture Corrector on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. There is one coupon right now! Check this out.
Link: Banggood product page
Coupon (22.79 USD): BG00c906
(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): BGG68285, BGSHHA, BGDG68285, BGSDG68285, BGF68285, BGSDSS, BG10OFFAFF1, BG4d9120, BGAlerabatod, 00c906
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Here is price history (for all/most countries) for KALOAD Smart Back Posture Corrector.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).