Aliexpress
Click here… to search for Broadlink RM4 Pro Smart IR/RF Remote Control on Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (42.76 USD): BGJUNEGSG9
Coupon (43.23 USD): hoNEYbGdeAlS
(CouponsFromChina.com tip: put item in your cart and apply coupon code there after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGd21f8f, 6GSGIT, BG3f30ef, BGD11063, BGB5074, BG949394, BG6f2068, ADMITAD2212, BGSmart6, BGAlerabat1, 8Couponsde, MVC8SPRING, 8BGwbg2204, tRaDetRaCKeR, 8wEbgaInS5
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Price history (for all/most countries) for Broadlink RM4 Pro Smart IR/RF Remote Control is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).