I would say $5-10~ for the WW HD display box. I bought 2 of those display boxes and a WW HD GameStop sign on here for around $15 total a few months ago.
Those Windwaker HD boxes were given away free from Gamestop if you were lucky enough to catch one. I seen them sell for up to 20 bucks for the right buyer, but I agree with Shane, probably 10-15 bucks.