I bought a rough, rattly, worn out springfield gi for 400 bucks. Then I bought springs, pins, ext slide stop, ext safety, ed brown grip safety, hammer, disc, etc etc and with a new set of grips all in all I spent about $400 on parts and tools, including a sear jig, and a checkering file. I welded up the barrel lugs and hood, recut them on the mill, (most of the barrell work could have been hand done with a file honestly,) and then welded up the rails and re-cut them to make the slide tighter on the frame. Fitting the slide after the weld/cut work took 2 hrs., the checkering all took 5 hrs, the hammer/sear/trigger work took 4 hrs, the bead blasting and polishing took 4 hrs. and oh yeah, I bob tailed the gun using the original main spring housing which required welding in the old spring hole and smoothing then checkering the flat, polishing the round edge, that alone took 5 or 6 hours.
What's my point? If you just want a gun to buy cheap and go shoot, do the 400 specials and go shoot. You'll end up with a gun that isn't special to anyone, and shoots about a three inch group at 25 yards, but hey, it's cheap, and that's okay.
If you want a reall project gun and have the tools and skill, (or desire to spend time learning to fullfill the project and enjoy earning the pride that goes with diligent work,) then do like I did, spend $800 bucks and about 40 hours of your free time after work on the project. If you do your homework and take pride in your work, it'll look nice when your done, be special to you and those in your club as they watch you learn and adore the process, and if you know how to tighten it up it'll shoot like mine, which is to say about an inch and 3/4 at 25 yards.
If you want the best, and want a status symbol piece drop 2500-3 grand or more on the name brand premium guns, and though you won't have any personal pride in its creation it'll be worth more as a status piece, and it should probably shoot under an inch and a half at 25 yards.
Now, you must decide what is important to you, and enjoy the decision, whatever it may be. I don't make any recommendations or insinuations on which path you choose, only that you do it safely, and with the constitution in mind.