Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (11.42 USD): BGe46870
Coupon (11.93 USD): BG00c906
(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): BG4d9120, BGAlerabatod, 00c906
(probably won’t work, but you can try them out)
Price history and price alert
Check out price history chart (for all/most countries) for IPRee Outdoor Double Tube 150db Whistle.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).