I am monitoring price for Countersink Drill Bit and it is for 6.96 USD now (in Banggood). You can create price alert here, copy coupons and view price history. You probably want to know what is the best price?
Latest coupon code price check (UTC time):
Banggood (6.96 USD)
Banggood warehouse is located in China. I have no active coupons for you right now. Price? From what I can see this price is higher than average price (5.50 USD).
Link: Banggood product page
Price: 6.96 USD
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BG20236Tool, BG589b2e
(you can check these old coupons out, but these probably won’t work)
Aliexpress
Click here… to search for 4pcs 3mm-6mm HSS Countersink Drill Bit Set on Aliexpress
Here are coupons that you can use.
Price history and price alert
Do you need price history chart (for all/most countries) for 4pcs 3mm-6mm HSS Countersink Drill Bit Set? There we go.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).