If it's your first and you are hell bent on G&G only then a lot of my friends recommended a Wildhog to me as a not too expensive weapon with ETU and Mosfet etc (around £200 - £250 depending on where you buy from) which allowed me to budget for 2 extra mags, 2 batteries, a charger, weapon case etc also (do make sure to figure those into your budget if it is your first weapon, you're probably looking at least £50-100 extra on top of the weapon itself)).
I went to a physical store to get hands on and a feel for the weapon and ended up spending a little more and getting a G&G Predator personally, which has pretty much the same features but just looked a bit cooler more than anything else. There's the CM16 variant which is polymer body and the GC16 variant which is steel body (if I recall correctly). You'd probably want to change the stock as batteries can be a bit of a tight fit (though they will fit if you get the right type). It felt nice and comfortable, and has a nice fire rate.
I am sure more experienced players here will be able to give you a whole range of diverse information and maybe even recommend better brands or models, but as a new player this was my experience purchasing a new G&G weapon personally. I definitely recommend going into a store and getting some hands on if you are able to.