Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. Too bad there’s no coupon right now 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): BGTACC18, BG589b2e, BGHTT15, BG20236Tool
(probably won’t work, but you can try them out)
Price history and price alert
Here is price history (for all/most countries) for Drillpro 12pcs 15mm-50mm Hole Saw Tooth Kit.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).