This is always an interesting question and probably ever builder with limited resources would be wise to prioritize future equipment purchases. Of course the longer one can wait the more likely it is they will find a really good deal on something specific.
Peterpan1 had some excellent thoughts. I mostly agree with his #1 and 2 and particularly the final paragraph. Since I also have stainless steel laser cut and etched fixtures for sale it isn't appropriate to comment more about that. You took the mill and lathe options off the table, so my suggestion for an immediate-need-to-get would be a decent sized surface plate. If I was only doing a frame or two a year I could maybe get by with just a beam or milling table but at your ambitious rate I would definitely want something close to 3' X 4'. This would not only make sure frames are straight but could also be jerry-rigged with V blocks (or something) to substitute as a fixture.
Of course I would get the O/A equipment first with the prep tools not far behind. Having tried many over the years (I've got Campy, Var, Park) my favorite for the money is Cyclus.
I could also never be without a lug vise.
Good luck with your personal efforts to improve the American economy.