if you are into m4s, the CM line is a good place to start around the 200$ mark. The gearbox shell is a bit weak but nothing a couple mods can't fix. The gun itself is very receptive of off the shelf parts and is fairly consistent from one manufacturing run vs the next, so no new issues generally come up.
If you are into AKs, it gets a bit sketchy as you there are good guns at around 200$ and bad guns in that range... all from the same company, though this is more to do with what replica it was cloned from, TM vs VFC. For AKs in the low end price range but reasonable quality, look at CYMA.
outside of that, the guns get more expensive for the aesthetics and components like mags and gear. Gear for m4s and aks is the cheapest as it's the most commonly available and real surplus is dirt cheap, as well as airsoft market stuff.
I futz with V2s, V3s and V6s. I could be wrong... but probably, most likely not, as far as I know.