Dude, just so you know it will probably break in less than a month but airsoft megastore sells a m5 for 36 bucks
www.airsoft51.com best website for the deals you get
There is no such thing as a good AEG for under $50. if you want even close to reliability youd have to be ready to spend between $150-200
The most expensive.
get a well m4 or m16 off of airsplat.com but you could get better ones for not much more off airsoftgi.com
The one that you shoot the best.
If you are just starting airsoft i would highly recommend an aeg, (airsoft electric gun) but if you are pro and experienced, a trained camouflaged sniper is the best, an invisible predator. However it does depend on the user of the gun. If you are asking performance wise then g&g makes the best airsoft guns on the market. (currently in the US)
a cheap airsoft pistol. its a lot of fun
Light .18 gram bbs.
the only fmg9 available is the magpul fpg, which is over 100 dollars.
Well I have a couple of links I will include
No airsoft gun under $100 is going to last for more than a few games, so none are truly "good"
The best airsoft gun you could get for $150 would probably be an Aftermath gun, but you could get a JG M4 or M16 for under $150