Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (29.99 USD): BG31JAN2023B
Coupon (38.53 USD): BG589b2e
(CouponsFromChina.com tip: apply code in your basket (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): BGd3032d, BG7e8848, BGHB218, BGeddba2, BG05ee70, BG667441, BGbfcdac, BGfe5f9b, BGde01fa, BGdb8659, BG9435b7, Cuponation9, BG75597c, BGe488a0, BG2c6718, BGdf9425, BG22ff55, BGd0a191, BGfd2fab, BG9ffd05
(probably won’t work, but you can try them out)
Price history and price alert
Here is price history (for all/most countries) for SKG 4098 Cervical Spine Massager.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).