I know people have a lot of things to say about these... but:
For around $500 I got a brand new KWA M4 CQB, and I've used it for a number of months in sand and rain... and it's a beast. 7.2v lipo and it's snappy, zippy, and shooting a consistent 349fps, so it's great outdoors and spicy indoors.
Total, I spent about $1000 on the gun, 10 mags, Classic Army RIS, batterybox, and two batteries (add +$150) for a charger.
Here's the teaser:
Ár skal rísa, sá er annars vill
fé eða fjör hafa. Sjaldan liggjandi úlfur
lær um getur né sofandi maður sigur.