So cheap, it’s practically in beta: $23.99 from Banggood. SONOFF TRVZB Smart Zigbe Thermostatic Radiator Valve Intelligent Thermostat Temperature Controller APP&Voice Control Work with Alexa Google Home.
Updated: 04-07-2025
Banggood
Warehouse in China.
Link: SONOFF TRVZB Smart Zigbee Thermostatic Radiator Valve
Regular price: $24.99
$23.99 with coupon: BGcd2e07
Additional Banggood coupons:
1. First page
2. Second page
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – SONOFF TRVZB Smart Zigbee Thermostatic Radiator Valve [EU] ($38.99)
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.
Price history and price alert
Do you need price history chart (for all/most countries) for SONOFF TRVZB Smart Zigbee Thermostatic Radiator Valve? There we go. The lowest price was: $20.99.
Price records source(s): 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)).