Several airforces around the world (Portugal and Chile) aren't that concerned about the airframe left on these aircraft apparently (having already bought considerable numbers) and many airforces (USAF, Netherlands, Taiwan and Pakistan notably) are running significant F-16 life extension programs, which provide a fairly cost effective option and offer up to 50% more airframe life. At 200 hours per year (a fairly high usage rate) that gives you 20 more years of effective life...I'm worried about the flying hours left in those second-hand birds.
The USAF is about to increase about 300x F-16's to 12,000 hour airframe life spans, due to F-35 delays. I imagine it would be rather cost effective to run 24 upgraded fighters off the back of such an upgrade too.
With a bit of creative thinking, it might be possible to establish a local upgrade facility and perhaps run some Korean or Japanese based USAF F-16's through a joint upgrade program, to make it economically viable and improve domestic aerospace capability as well as your own ability to support modern fighter aircraft.
Alternatively piggy-backing onto Taiwan's F-16 upgrade may provide a useful secondary option, that would allow a fairly handy aircraft if your country pursued all the options, including AESA radar etc.