Here is a link to a
$8 mill for cutting slots in angle. The amazing thin about a mill like this is it uses no electricity and can fit in pretty much any tool box. It is significantly less danergous that a vertical mill, and can actually do more precise cuts. I took a jewelry and metal smithing calss at Purdue. One of the first assignments was to cut out the profile of Lincoln out of a penny. It was pretty cheap practice and helped showcase the tools skills.
While I couldn't find a picture of a penny, I did find this picture of
something similar done to a quarter (much harder metal):
While some might think it would take a long time to do such a thing, the lincoln profile took about 35 minutes with a beginner skill level. Sawing a couple straight lines after dilling 2 holes would likely require less time than locating edges in a mill.