Basically copy coupon, view price history or create e-mail price alert. You probably want to know what is the best price?
Firmware target: HappyModel_ES24TX_Pro_Series_2400_TX, RF Output Power: >30dBm, RF chip: SX1281IMLTRT, Minimum receiver refresh rate: 25Hz, JR standard 5pin socket, Regulatory Domain: ISM2400, Weight: 51gram(without antenna）, MCU: ESP32(main) /ESP8285(aux / as espbackpack), Antenna gain: 4.18dBi, Dimension: 70*49*32.5 mm, Frequency Range: 2400 MHz to 2500 MHz, Item Name: ES24TX Pro Micro TX Module, Power supply voltage: 5v~10v, Maximum receive refresh rate: 500Hz, Model: ES24TX Pro, Brand Name: Happymodel
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
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/5cd
Old coupons (from the oldest to the newest): BGRCParts8, Tabby20, MVC8SPRING, 8BGwbg2204, 8wEbgaInS5, pROMo8cuPoN, BG8RCToy, hoNEYbGdeAlS, BGJUNEGSG9, BGRADIORU, BGToys8, BGSaleFeb8, BGMatt2022, BG589b2e, BG8FORMULAMX
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Here is price history (for all/most countries) for HappyModel ES24TX Pro 2.4GHz 1000mW ExpressLRS ELRS RC Micro TX Module.
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)).