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 right now! Check this out.
Link: Banggood product page
Coupon (47.81 USD): BGGines
(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): BGe95db2, BGDRB18, BGTools8, BGTACC18
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Check out price history chart (for all/most countries) for Drillpro 51Pcs 1-6mm M35 Cobalt Drill Bit Set.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).