Can't go wrong with a mig. There is a few things it can't do but its a good rounder for the car and general home work.
See about a mig that can do both gas and gasless.
Arc welder is ok, but its better for heavy work, like thick steel and welding general crap together out the backside of burke. If you look into the higher priced arc welders you'll also be able to do....
Tig is more of a specialized welder for making beautiful looking welds on exhaust pipe, suspension parts etc.
Go for a gas/gasless mig. The gas mig is by far the easiest to learn, but the bottles can get expensive and there's times when using a shielding gas is pointless (outside springs to mind)
:yes: you can
But, it can be expensive. Need a gas bottle (Argon ?), wire that can weld aluminum and a welder that can turn the voltage down.