Lot's of good older Citation I's and II's are "cheap" good I's are under $500K, when I say good, I mean low time engines or fresh hot sections, decent paint and interior and some have upgraded avionics. I'd say you could buy a late 70's Citation I/SP for $400K with fresh inspections and fly it for the cost of fuel for the next 12-18 months until the next phase inspections are due.

BUT, then the fun wears off.

1-4 inspections are $10K plus squawks and jets that are nearly 40 years old have expensive squawks!
They burn a lot of fuel, I's will burn 175 gallons the first hour and 120-130 or so the second hour IIRC.

I planned 200 gallons the first hour and 160 in my II, that was pretty close.
Lots of old systems, that while reliable, are very expensive when they break.
http://www.controller.com/listingsd...TION-ISP/1979-CESSNA-CITATION-ISP/1305227.htm
http://www.controller.com/listingsd...TION-ISP/1977-CESSNA-CITATION-ISP/1249045.htm