non-condensing, Compatible Protocol ZigBee3.0, Homekit, bluetooth & bluetooth Mesh, Size 90x25mm, Support System Android 5.0 or iOS 12.0 or above, Working Humidity 0%-95%RH, Working Temperature -5℃-50℃, Model ZNDMWG03LM, 2.4G WIFI, Rated Input 5V/1A.
Just check coupons out (with price alert and history). What is the best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. 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
1. ($33.99): BG1c17c8
2. ($43.67): Cuponation9
3. ($44.15): BG8ReviTrage
put item in your cart and apply coupon code there after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/i1u
Old coupons (from the oldest to the newest): BGMGA2, BGXMZB3, BG25GTW, BGGA25, BGTY2K, BWGWXm1, BGGW24, BGXMG3, 2020CNY, BGFT245, BGVDay10%off, BG765A, BG248G, BGHOMEG12, BGXMGW03, BGGXMZB3, BGSAMH, BGXMGTW, BGXMGWSP, bGhOnEy10, BGXMGWG, BG47595, BGSMOFF, BGXMZG7, bgshOOp10, BGUSACZ599, BGRZIGBEE, BgcLuBofErtA10, BGXMGWEX, BGXMGWH, BGXMGA, BGXMGWB, BGXMFRL, BGXMGTWY, BGXMGAWY, BGXMGW, BGAFF10OFF, BGXMGWAC, BGXMGWAH, BGXMGWHK, BGCuponation10, BGXMGWCN, BGXMGAWYSS, 13f142, BGXMGAG, BGHONEY2110, BGfe2e93, BGb166bf, BGSHOM15, BGd7e281, BGd58271, BG9f4971, BGddc553, BG10b179, BG1738ba, BGb32a05, BGSHE15, BGGROC595, BGSPD595, BGSP595, BGHUOG595, BGISOG595, BGfa729b, BGCL595, BGRU595, BGcou924, BGNDH57, 6GSGIT, BGD11595, BGaf1e4c, BGd25f67, BGD11039, BGa4c593, BGB5047, BGbb9148, BG5ba78c, BGbcf327, ADMITAD2212, BGe1636a, BGSmart6, BG9976ea, 8wEbgaInS5, pROMo8cuPoN, hoNEYbGdeAlS, BGJUNEGSG9
(I don’t think these’re gonna work, but you can try ’em out anyway)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – Xiaomi Multimode ZigBee 3.0 WIFI Bluetooth Smart Home Gateway [EU] ($-3)
Price history and price alert
Check out price history chart (for all/most countries) for Xiaomi Multimode ZigBee 3.0 WIFI Bluetooth Smart Home Gateway. The lowest price was: $17.99.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
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)).