Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. Too bad there’s no coupon right now in Banggood.
Link: Banggood product page
Price: -3 USD
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGXIN603, BGBFHOME9, BGDESE603, BGCNOximeter, BGDETD603, BGDEFO603, BGKN603, BGOXMI, BGJASE603, BGJAFO603, BGCJ603, BGFEFO603, BGMARFR603, BGITMA603, BGMRDC17, BGGR603, BGNIT603, BGMAYWK603, BGHONEY2110, BGJUSE603, BGisly603, BGPDhome33, BGEUYB603, BGTYOC603, BGAU603, BGSPHOME26, BANGGOODSD, BGUdb35, BGUbf30, 00c906, BGHealth10D, BGHU1582, BG4dd395, 2022ACTIESNL, BGHB218, BGHU1867, BGMHO07, BG4ee866, BGHOM113, BGe79187, BG5ca0a2, Cuponation9, BG41aded, BG75597c
(there’s a little possibility that old coupon will work)
Price history and price alert
Here is price history (for all/most countries) for Boxym Smart Bluetooth 5.1 Pulse Oximeter.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).