I don't think Chavez would help with the Pampa isn't there parts in or part designed by a US company? I don't think he'll do a single thing that involves anything America period. If Argentina signed deals with China I think he'll turn into Argentina's best friend.
The K-8 been around a while and is a proven basic jet trainer. Egypt bought a production line and has a large number of them but I think they may have done also to build industry to help there economy. There about 10,11 or so users spread out around the world and Egypt is the biggest user besides China. If you wanted to dig and get more facts and details Google it you'll get tons of information.
I think a better choice for Argentina until more funding becomes available might be a high end advance trainer type. This way your pilots fly a modern or semi modern aircraft and get in important stick time and your ground crews get in there maintenance hours. This way you don't lose the skill set needed for a modern AF, A-4 etc don't cut anymore. It may sound a little crazy but buying say 16 Chinese L-15/Yak-130 for the price value and train up a bunch of pilots and crew. Wait to buy any 4th generation fighter because in four or five years many more will be around for sale and better deals will be found.
When F-35 become real and go active or even before when the different countries start training and shooting off there mouths on how great there are, 4th generation go on sale and drop in value right there.
Countries with:
A,B,C,D Hornets
A,B,C,D Vipers (Turkey might be a source for one big user) in general over 4,000 produced so there out there
Su-27 and early Su-30s (Russian early model slap in a new radar,engine, and new weapons suite and you have yourself a interceptor don't have to go with the full Su-30 work up)
Mirage 2000-C, maybe even Mirage 2000-5 types. If France makes a big C/M Rafale F3 Block sale maybe even early model Rafale's
Gripen A,B, maybe C,D if the newer model gets customers
Russia, Ukraine, still have large numbers of Mig-29s. In a few years MIG will be able to slap in more of the Indian K model upgrade and maybe a ASEA radar. Ukraine has I believe 200+ Fulcrums who knows maybe five years from now they could be made into mini MKI Fulcrums.
Early batches of FC-1/JF-17 might be out there, ?
Early model J-10? rare
I guess what I'm saying badly is if Argentina can make A-4s work, upgraded Fulcrums, ex-Spain F/A-18, or ex-Turkey Vipers, etc, would be a jump up. If Chile's doesn't buy stealth down the road you wouldn't even be that far behind really.
No reason Colombia couldn't cash in on this as well the key is getting the 5th generation aircraft into production and produced.
So I think good deals on 4th Generation fighters are a few years away, just my two cents.