Xiaomi Aqara Window Door Sensor [EU] (Banggood, Aliexpress: ZigBee Wireless Connection / APP Control / Multi-purpose Smart Home Security Equipment (the best price with coupon)).
Check coupons or create price alert down below. Let’s see what best price is ATM.
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in Europe 
. There are no coupons for this product in Banggood. There’s only 1 record in my database, so I have no idea if the price is OK.
Link: Banggood product page
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): 10XMA, 20XMAQ, d173d2, 256310, DAQIR, 360878, BGMAQDS, affiliate6, aff7off, BG7AQDWS, bgssaff9, BGaDmITAd, BGAQDSS9, 13f142, BGhumankit, BGBFAFF2019, BGAQDSS1, BGCITYADS2019, BGZIGBEEPL, BGAQDS, BGAQ20, BGHOMEAPP, BGAQA15, BGAQDS04, bGhOnEy10, BGSM15, BGSMOFF, BGAQWDS7, BGAQADOORS, bgshOOp10, BGAQDSUK, BGSAMRTH, BGN7CND, BgcLuBofErtA10, BGAQDSH, BGAQDSB, BGAQDSU, BG15SH12, BGAFF10OFF, BGSTHO15, BGAQZUK, BGAARDS1, BGCuponation10, BGAARDS2, BGAQDSSS, BG3d0660, BGd2c614, BGHONEY2110, BGSHOM15, BG571878, BG133c4e, BG40bece, BG200eff, BG78a9e0, BG87e1d2, BG46ecc4, BG0086c3, BGZJ323, BGGROC323, BGcou323, BGSLO323, BG115048, BG35eaee, BG015156, BGCL1323, BGCL323, BGHO323, BGcou925, BGNDH59, BG2f4c49, 6GSGIT, BGf3a810, BGD11047, BG15d2dc, BGB5059, ADMITAD2212, BGSmart6, BGHU1863, BGPLWIOSNA62, MVC8SPRING, 8BGwbg2204, pROMo8cuPoN, BGJUNEGSG9, Cuponation9, 9OFFSUMMER, BG8ReviTrage
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. China – Xiaomi Aqara Window Door Sensor ($-3)
Price history and price alert
There is only one database record (it was for $12.99), so you can’t see price history chart.
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).