Aluminium plates are very cheap. 2.5mm plates (what im using). cost only 1.9dollars per square feet (that is im in Switzerland so they are probably cheaper in the US).
If you are cutting aluminium plates you will need a pair of metal cutter sheers. 5-20 dollars
And for cutting holes you can just use a normal drill head (note if you want to cut rectangles, like the 2 holes on each side of the ma5c you will need a special drill bit which will allow you to drag it so that you can extend the hole).