Thinking of selling old Ps2 to buy new one, help please

[Ichiri]

Hi I have a Ps2 that I bought on release day so its a version 1, its a scph 30001 model U1 with 10 screws at the base, so what I wanted to do is get a new Ps2 so I can install a modchip to it and play backups since I have a Dvd+r and my Ps2 doesnt read those. Where should I sell mine and how much ( the front part of the cd tray its a bit loose because of the gameshark swap trick ) ? And where should I buy one, if I can get one modded then much better that can play Dvd+r backups as well. Thanks for any reply.