One of if not the most experience drone operating countries is iran, probably considered the third world. Long before america was using drones daily, iran was already highly experienced in using them, I have not heard of them using armed drones but that is easy modification for a country that has been making them for decades.
Infact being the third world well depending on what you call third world might have played a role in their drone program, after the shah was overhtrown, buying spyplanes from america was out of the question, and the mig25 which was awesome as a spyplane and as an interceptor and horrible at everything else jet related was probably out of irans budget, while building drones was cheap and drones getting lost or being destroyed hurt their wallet far less than let's say a bunch of mig 25's that could multiple times as much and could easily be lost by any pilot untrained, as well as the fact top speed on a mig25 was for intercept and escape only, also meaning some untrained moron would push it to speed levels of an sr71 blackbird, which the jet could do but not without serious engine damage.
Given their options I see drones if not being an effective force to first world but atleast being cost effective for their needs, and any third world country can build drones if iran could for decades. Also at 3 million per drone that is not too bad, buying jets from the cheapest suppliers russia and france(russian jets lately have been getting pricey, as have french ones)mseems to be far more expensive for a mainline weapon especially one used where you know it will be shot down. Imagine it like tomohawk cruise missiles for the third world, expensive but still cheaper than losing real gear.