Tacklife Direct via Amazon offers the Tacklife 10-Piece Diamond Drill Bit Set in Silver for $14.97. Coupon code "5YD7T4ZF" cuts the price to $11.23. With free shipping for Prime members, that's $4 off list and the lowest price we could find, although we saw it for a buck less last month. They come in 10 sizes, ranging from 6mm to 50mm, and feature diamond coating. Deal ends January 17.