Aliexpress
Click here… to search for NUX Mighty Air Wireless Guitar Amplifier on Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (239.08 USD): BG1d402f
Coupon (249.70 USD): BG00c906
(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): BGNUX07, 7bcdf9, BGNUX0707, BANGGOODSD, BG1081b2, 00c906, BG423938, ADMITAD2212
(there’s a little possibility that old coupon will work)
Price history and price alert
Price history (for all/most countries) for NUX Mighty Air Wireless Guitar Amplifier is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).