Basically copy coupon, view price history or create e-mail price alert. What is best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Battery type Polymer lithium battery, Size 162x53x22mm, Number of channels 99, Charging method USB charging, Standby time 2-3 days, Weight 100g, Transmitting power ≤5W, Rated voltage 3.7V, Communication distance 1-5km, Frequency 430-440MHz, Battery capacity 1500mAh, Brand Baofeng BF-T9
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($42.49): tRaDetRaCKeR
2. ($42.49): 8wEbgaInS5
3. ($42.49): pROMo8cuPoN
4. ($42.96): 2203ActiesNL
5. ($43.42): BG00c906
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 and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BgcLuBofErtA10, BGAFF10OFF, BGCuponation10, 13f142, BGHONEY2110, BGd0b05d, 00c906, BGe46870, 2022ACTIESNL, Terence, Tabby20, BG1efeb0, 8Couponsde, MVC8SPRING, 8BGwbg2204
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Here is price history (for all/most countries) for Baofeng BF-T9 Walkie Talkie.
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)).