getting into a build?

So this summer,once the snow gets off the ground I am going to try to be getting a project car of Craig's list or a junk yard. What I plan on doing is get it running and install a large turbo and anti lag kit as far as performance mods go, right away at least. My question is,before I start, how much is stuff gonna cost for said mods? Like the indirect costs like an ecu and engine mapping etc. This will help me figure out my budget for the base car. And suggestions on good cheap rwd or awd cars are welcome.