To throw in some extra food for thought...
The dBoys M4 that a friend bought was not bad. Honestly, it wasent bad, it wasent great. Some suggestions though, Buy a new hop up unit and hop up rubber/nub ASAP. The stock one is absolutely horrid. He couldnt get any form of overhop (so he couldnt get a flat and level trajectory for the power he had) at all with .20's and with .23's they'd just drop real fast.
Having said that, I was impressed with the metal body though. Seemed on par with a CA Metal body, it's just the paint has a tendancy to flake off if you scratch it hard enough.
For the price, it's not bad, but be advised you will have to replace the hop up unit, and the hop up rubber and nub before it's even remotely close to a decent performer.
If your heart is dead set on an M16 or variant then save your money, as it stands right now, there is no M16/M4/w/e that meets my standards for under 250$.... the cheapest (and ironically one of the best) M16's you can buy, is a G&P M16A2 for about 230$ + shipping from Hong Kong (so about 260-280 shipped) Which isnt too bad. If your parents wont let you spend 300+ on an AEG then I think it's time you find a different hobby because it only gets more expensive as your desire to play more goes up...
I probably could have bought and restored a classic Mustang with all the money i've spent (read: wasted, in a sense, it is afterall a hobby) on airsoft.... probably not but it's rediculous how much I have spent over the past 4 years of playing.