Turbo's can be cheap too. Starting with a carb'd 302 Mustang, myself and a partner were able to get it turbocharged for under $300.

$100 GM 6.5 Diesel truck turbo, used, internal wastegate.
$75 Cheap eBay 50mm blow off valve
Less than $100 for a t3 flange, misc flanges, fittings

We used stock headers, cut up some old exhaust pies for tubing, and fabbed a carb hat, no intercooler. It sounds gross, but it really didn't look half bad. I wish I had pictures to prove it. Granted, this is an extreme example, and we definately did a lot of cutting and welding ourselves, but we really did it, and it really cost less than $300. The motor was stock with an e-cam, and made 340rwhp @ 10PSI, on Race Related's dyno. It ran great.

Brian
EFI-Unlimited