ive seen some people selling the fake followers and likes, ive even bought some. finding a reputable person is tough, and can be expensive. I was finding 10k likes and like 5k follower packs for around 15 to 20 bucks. Some promise a specific number and dont deliver. Ive also had some just disappear randomly. As far as the exact method on how they do it, I am unsure. I assume like you said it is a script that just creates accounts rapidly based off of generic info. I noticed that the times i did buy, alot of the names and pics were similar. Just my thoughts.