Magene H303 Heart Rate Sensor (Banggood, Aliexpress: Weight 108g, Size 62.3*35.1*11.5mm, Model H303, HR Accuracy ±1BPM, Brand Magene, Waterproof IPX7, HR Unit BPM, Support Object Cycling APP /Bike Trainer / Stopwatch / Sport Watch / etc., Color Black, Battery CR2032, HR Range 30-240BRM, Connection Mode bluetooth4.2 ANT+ (the best price with coupon)).
Basically copy coupon, view price history or create e-mail price alert. Let’s see what best price is ATM.
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 price update (UTC time):
Banggood
Banggood warehouse is located in China. I couldn’t find any coupon for this product on latest product update.
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/feV
Old coupons (from the oldest to the newest): BG2073d2
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Check out price history chart (for all/most countries) for Magene H303 Heart Rate Sensor. The lowest price was: $29.99.
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)).