These are the cheapest bits suitable for drilling metals and usually, come with a black coating to help prevent corrosion (when undamaged) and slightly extend life. There are several advanced coatings which extend the life of this type of bit and might help to prevent damage if you are a bit lax about cooling and lubrication.

Hi-Spec 99pc Complete HSS Mixed Drill Bit Set. 1 to 10mm Titanium Coated High Speed Steel Drill Bits for Metal, Wood & Plastic. All In a Box Case
4.0

3PCS HSS Step Bits, High Speed Steel Step Drill Bits Set - (4-12mm, 4-20mm and 4-32 mm) Cone Drill Bits Hole Cutter for Wood, Stainless Steel, Sheet Metal by...
5.0

hep® 13pc Titanium Coated Hss Drill Bit High Speed Twist Steel drill Bit 1/4" Hex With Holder For wood, metal, aluminium
4.0