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)).
Go down and check coupons out. Remember to check price history if it is available. 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 price update (UTC time):
Banggood
Banggood warehouse is located in China. Too bad there’s no coupon right now in Banggood.
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): BG2073d2
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Price history (for all/most countries) for Magene H303 Heart Rate Sensor is here. 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)).