How much could I sell a PS2 slim for?

May be...

Figured there's no point in keeping it, so I'm looking to get rid of it.

it matters about the condition, if its in a pretty good condition then you should be able to sell it for around 70-90 bucks, but if you trashed it or its condition isnt so good then the price drops could drop to 50 or even less

Probably 50-60$

80 bucks