Here's the rough cost of my AEGs so far...
CA M15A4: About $725 (including battery and charger)
C8A2: at about $1000 so far, and still needs work
Real Sword Type 56: $890
JG H&K 416: $360
JG MP5-J: $280
A&K M249: got it on a trade, but they sell for close to $800.
And that's NOT including several hundred dollars' worth of upgrades and accessories.