Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. Well, there is one coupon available right now.
Link: Banggood product page
Coupon (27.13 USD): BG00c906
(CouponsFromChina.com tip: coupon code has to be applied in shop’s 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): BGAFF10OFF, BGCuponation10, 13f142, BGHONEY2110, BGd0b05d, BG2589f4, 00c906
(there’s a little possibility that old coupon will work)
Price history and price alert
Here is price history (for all/most countries) for Retevis H777 Walkie Talkie.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).