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Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (25.52 USD): BG75597c
Coupon (27.32 USD): Cuponation9
Coupon (27.62 USD): BG8ReviTrage
Coupon (28.22 USD): BG00c906
(CouponsFromChina.com tip: put item in your cart and apply coupon code there 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): BGNOTD344, BgcLuBofErtA10, BGBFHOME18, BGAFF10OFF, BGJATD344, BGFEFO344, BGCuponation10, 13f142, BGHONEY2110, BGZX344, BGZXFO344, BGLYFR344, BGPDhome74, BANGGOODSD, BGTYOL344, BGHUOL344, BGUbf68, BGHU1314, 00c906, BGXPJA136, BGQCHD1, BGHealth10D, 2022ACTIESNL, BGXPFE910, BGHUMA21, BGMAYB235, BGCCHU108, BGHB218, BGXPMA063, BGHECARE1, BG4ee866, BGf1732e, BG03c941, BG4daac6, BG291e2f, 9OFFSUMMER, BGc3635b
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Check out price history chart (for all/most countries) for Thermodock Non-contact IR Infrared Thermometer.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).