Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. One coupon is available. Cool!
Link: Banggood product page
Coupon (39.99 USD): BGb2462c
(CouponsFromChina.com tip: just apply this code 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): BGPump609, BGwhielabel, BGInflator27, 13f142, BGJUP12, BG9074ac, BG10OFFAFF1, BGb5f9e1, BGbe4ecd, BGbd95c5, BG58b710, BG573583, BG367827, BGd927e9, BG08af91, BG00c906, ADMITAD2212, 2022ACTIESNL, Terence, 2203ActiesNL, BG1efeb0, 8Couponsde, MVC8SPRING, BG64e8d1, 8BGwbg2204, tRaDetRaCKeR, BG78b55c, BGfc41d0, BG037666, BG92c5a0, BGc0d44a
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Price history (for all/most countries) for AUDEW AC/DC Digital Air Pump is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).