Aliexpress
Click here… to search for BAOFENG DM-5R Walkie Talkie US Plug on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (57.85 USD): BGAFF10OFF
Coupon (57.85 USD): BgcLuBofErtA10
(CouponsFromChina.com tip: this code has to be applied in your cart 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): elec, e2bcea, fd2bd0, AFfbG10, BGBFAFF2019, BGCITYADS2019, BGE13, bGhOnEy10, BGdragonBoat, BGSS10%SW, BgoFErTaSchInA10, BGELIG0920
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Here is price history (for all/most countries) for BAOFENG DM-5R Walkie Talkie US Plug.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).