Aliexpress
Click here… to search for 50 pcs. 1/1.5/2/2.5/3mm HSS Titanium Coated Drill Set [EU] on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in Europe 
. I don’t really know if this price is reasonable, coz there’s no price history in my DB. I found coupon for you. Check this out.
Link: Banggood product page
Coupon (5.03 USD): BGGines
(CouponsFromChina.com tip: this code has to be applied 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): BgcLuBofErtA10, BGBITS888, BGAFF10OFF, BGCuponation10, BGHONEY2110
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Price history and price alert
Price history is not available for this item (not enough database records)! The lowest price was 3.99 USD though.
You can set price alert (for Banggood).