Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. I found coupon for you. Check this out.
Link: Banggood product page
Coupon (21.47 USD): ADMITAD2212
(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): e2bcea, elec, BG3dgeek3, AFfbG10, 502C6B, BGBFAFF2019, BGE13, BGAFF10OFF, 13f142, bgshOOp10, BGELIG0920, BgcLuBofErtA10, BGCuponation10, BGHONEY2110, BGd0b05d
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Check out price history chart (for all/most countries) for Practical 6-36V Auto Leveling Sensor for 3D Printer.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).