For AK's, I have owned a dboys ak74, a plastic cyma ak47 and I currently have a g&g top tech rk47.
The dboys I had was a piece of junk, multiple internal parts broke in no time at all and even after fixing it a couple times it kept breaking the stock parts, I also had a dboys pdw which had some major build quality issues, I would avoid the dboys.
The Cyma worked fairly well for being a cheap plastic gun, externally it had some wobbly parts and didn't feel all that solid but the gearbox just kept going. Of the economical AK choices I would say Cyma is one of the better ones.
My G&G RK47 is a beautiful gun, practically no wobble, external parts are all high quality and it shoots hard and straight like it should. G&G does a great job with quality control on their high end guns, their quality control seems to go down a lot with their lower priced guns, but the internal parts are usually still pretty good for what you pay.
As for other guns, I agree with those who suggest the full metal KA M4, it's one of the best starters on the market.
Make sure you are budgeting for your other gear too, a good set of goggles goes a long way. Doesn't matter what gun you're carrying if you can't see.