We have used this online supplier and like them. You can specify the blade type, width, tooth pitch, length, and they will custom make it and ship it very quickly at a very good price. ==>
www.probandsawworks.com
Opinions: Order a wide blade (3/4) for staight cutoffs through heavy material, AND a narrower blade (3/8) for curved/shaped cuts through thinner material. Go with a high TPI (teeth per inch) of 14-18 so you can cut sheet and thin stock without snagging. It will also cut thicker stock, just slower. If you are cutting aluminum almost exclusively as most FRC teams are, a plain high-carbon steel blade will last a long time for about 1/3 the cost of a bi-metal blade. For the cost of bi-metal you could buy a couple of different widths, TPI's, or spares and be well set.