I get my blades through Rio Grande in New Mexico. Fast service. I generally buy a gross of whatever blades I require. They come by the dozen.
I keep various sizes on hand, 5-0, 2-0 (my most-used size), 3, 5, and 8. All will cut brass, steel, wood, aluminum, fingers. I did use my saw to cut parts for airplanes from 4130 steel, thicknesses up to 0.125. Do use the blade lube, either bees wax or the Rio Grande product "BurLife". This can also be used on drill bits as a good lube. BoeLube is about the same thing.
Cut smoothly, and don't try to force the blade into the cut.