If you stick within the Fender Universe, the sheer number of drop-in compatible parts is mind-boggling. Thats the "mutt" approach, and you'll end up with exactly what you want, but it wont be cheaper than a Harley Benton. The postage alone will eat you alive unless you have Amazon prime though. Ive built one kit bass, but it was years ago, and the quality of the parts was....meh. I have since built three entirely scratch-built basses, two of them Rickenbacker clones that, on paper, cost less to build than a genuime Ric, but not if you factor in buying some tools I needed to build them. I suppose that gets amortized over subsequent builds. It was never about saving money anyway, the craft itself is addictive. In the case of a Mutt build, its like a Treasure Hunt that can also be weirdly fascinating. Like everyone else, I found out the hard way way that a flawless factory shiny paint finish is really hard to achieve in your garage, but something like Tru-Oil, or other simple natural finish is pretty easy. If you want a painted finish, lots of pre-painted bodies out there for relatively cheap.