depends on how you define good. having pneumatic and electric tools like an air-nibbler, hydraulic lift, air-saw, impact wrench, and so on are a huge help for doing serious work, as are power tools like a circular saw, arbor/table saw, band saw, scroll saw, jigsaw, drill press, router, and so forth. There are a number of specialized tools as well for things like body work, removing particular items like door handles, window cranks, and body panels with plastic cotters, some factory units need special removal tools as well (Datsuns, Fords, etc) If you want to get into fiberlgass work you'll need more tools beyond the above.
There really isn't a "best" system. If there was, everyone would have it as a goal and you'd have heard about it by now. As far as cheap goes, JBL makes some of the cheapest good amps. How much are you looking to spend on component speakers and subs?
Save up more money! Building a box is harder and more time consuming than you think. If you have minimul knowlege about tools (not tin snips and screwdrivers) than dont build a box. You have to know and do alot of prep work before you build.