I have just checked coupons. The lowest price I could get is $41.39 for iRangeX IRX4 2.4G RC TX Module With Case (in Banggood). Basically copy coupon, view price history or create e-mail price alert. Do you want to know what the best price is?
Antenna Length: About 108mm, Firmware: STM32, Band: 2.4G, Item Name: IRX4, Weight: About 40g, Dimension: About 49x22x65mm
Latest coupon and price update (UTC):
Banggood ($41.39)
Banggood warehouse is located in China. Coupons for iRangeX IRX4 2.4G RC TX Module With Case? Nope, there’re no coupons in Banggood. Is it expensive? This price is higher than average price ($32.52) for this item.
Link: Banggood product page
Price: $41.39
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGMD10, BGVDay10%off, BGIRX4, FBCOUPON1, BGIRX420, bGhOnEy10, Parts8, BGSS10%SW, bgshOOp10, BGRC902, BGRCRR9, BGCuponation10, BGDAVIS, BG70e5fc, BGGAL8, BGRCParts8, Tabby20, BG1efeb0, 8Couponsde, MVC8SPRING, 8BGwbg2204, tRaDetRaCKeR, 8wEbgaInS5, pROMo8cuPoN, BG8RCToy, hoNEYbGdeAlS, BGJUNEGSG9, BGRCT10, BGRADIORU, BGToys8, BGMatt2022, BG589b2e, BG8FORMULAMX
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
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
Check out price history chart (for all/most countries) for iRangeX IRX4 2.4G RC TX Module With Case.
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)).