Aliexpress
Click here… to search for Getinfit Adjustable Back Posture Corrector on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. Well, there is one coupon available right now.
Link: Banggood product page
Coupon (14.06 USD): BG589b2e
(CouponsFromChina.com tip: apply it in your 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): BGBCC714, 13f142, BG10OFFAFF1, BGHealth06, BGBCE714, 00c906, BG00c906, BGHealth10D, 2022ACTIESNL, BGHB218, 2203ActiesNL, BGHECARE1, BG4ee866, TTSUMMER8, Cuponation9, BG75597c
(probably won’t work, but you can try them out)
Price history and price alert
Here is price history (for all/most countries) for Getinfit Adjustable Back Posture Corrector.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).