I've got close to $600 in my first violin and still need varnish and strings. I used one-piece front and back so I didn't need a plane. I made my own form, calipers, bending iron, and purfling cutter. I purchased 2 pfeil gouges, 3 Chinese finger planes, scrapers, various sharpeners, a couple books and wood of course. It would be very difficult to do it much cheaper.
That said, buying nicer tools would have made it much easier and faster. A wise man once told me, "Without the right tools, it's just work."