I did my Megasquirt/TPI for like $400, then probably another $100 to go distributorless, then sold off all the old parts and got like $175 back out. There was quite a bit of planning, labor and learning involved, though.
People avoid having to learn how to tune and spend big money to do it. But over the course of the years, you may spend just as much time scratching your head and turning to tech support / shops to fix the issues that come up. How many people say "Darn, I wish I never wasted time learning how to build an engine" or "what a shame I learned a useless skill like setting up gears".
) and found a front end wrecked '89 K5 that I purchased for $900. I sold the 700r4 that was in my k5 for $400, and swapped in the entire TBI motor and tranny into it, reworked the harness, and then sold both 10 bolts for $100 each, and some other misc off it for another $100 or so. Then took shell and frame to scrap yard and got $200 for it. So I actually made out on top on the deal 
). But there are a lot of these out there. It does take more work on your part to complete the swap, but if cost is more the issue, great way to go
