Aliexpress
Click here… to search for Raitool 90 Degree Corner Tool on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. There is one coupon available! Pretty cool, huh?
Link: Banggood product page
Coupon (23.79 USD): BGherra
(CouponsFromChina.com tip: apply code in your basket (cart) after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Price history and price alert
Check out price history chart (for all/most countries) for Raitool 90 Degree Corner Tool.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).