[size=12]Without seeing it in person to feel if it's warped or look if it's cracked or has any other problems that aren't obvious in the photo, I'd say that $25 is a decent deal on that piece, but it's not like you absolutely stole it at that, either. It's a common griddle.
The first handle griddle I ever got was a 609 just like this. I paid more than $25 for it, too.
I don't know if that's heat damage or just rust. It does look almost like somebody used it with a small burner at some point in its life.[/size]