$20.99 – Tuya WiFi Natural Gas Detector Leakage Sensor (Banggood, Aliexpress: Tuya WiFi Natural Gas Detector Leakage Sensor LED Digital Display APP Remote Alarming Voice Reminder Troubleshooting Household Security Precaution Device (the best price with coupon)).
I have checked all old coupons and price is $20.99 for Tuya WiFi Natural Gas Detector Leakage Sensor (in Banggood). You can create price alert here, copy coupons and view price history. What is best price?
Latest coupon and price update (UTC):
Banggood ($20.99)
Banggood warehouse is located in China. There is no active coupon in my database right now (for Banggood). Price? This price is higher than average price ($15.99) for this item.
Link: Banggood product page
Price: $20.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BG1e91cc
(there’s a little possibility that old coupon will work)
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Here is price history (for all/most countries) for Tuya WiFi Natural Gas Detector Leakage Sensor. The lowest price was: $14.99.
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)).