I have 10 WE GBB mags. Which for me cost me R4500 (Rand) which in Canadian Dollars is $516... Plus the R3750 I paid for the gun (rand) which is $430
So thats around $846 for the stock standard gun and 10 mags. Then add all my accessories etc. Its close to $1000 converted.
But my stuff here in South Africa is a lot more expensive than it would be for you guys. But just shows you how much a GBBR will cost in the end.