Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. CouponsFromChina software could not find any coupon for this product in Banggood.
Link: Banggood product page
Price: -3 USD
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGfdd612, BGd5fb8d, BGb77532
(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 OWON XSA815TG 9kHz-1.5GHz Spectrum Analyzer.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).