I bought the G520 version used in 2004 for $50.00I used to have that monitor - remember paying around $500 for it in 2002(ish).
Someone gave me the G500 a couple years ago. They actually begged me to take it.
I almost ended up paying for it last night. Note to self: don't try to pick up a 70 lb monitor and then step over a baby gate onto water spilled on the kitchen floor...