I I would reccomed the we m4 aeg, look at the redwold tv review on youtube, its cheap, full metal and fairly customizable.
Your gunna want a mid price range, to cheap and you get bad experience and breaks, to expensive because you may not know your play style and pearsonal prefrences.
But thats just my opinion. Just look at mid ranged guns off shops and then look at reviews, hell even ask people on here about a gun your intrested in, also if you go to your localmsite you can rent a gun, giv you a feel of how you play and other players may let you examine their shooters if you ask nicely