I have a Classic (Big) PS2?

May be...

I want to sell it to get a PS2 slim where can I sell it e.g shops-I live in New Zealand so preferably New Zealand Shops

you should just keep it because i have both and there isnt a difference exept size

i agree with that answer ^ and the only differince is that the slim has a built in network adapter , but if u want 1 of those ill sell u 1 for cheap? steelerfan00789@yahoo.com

ebay is your best bet, much bigger market