Here is a link on this very forum to a Casascius Coin owned by forum member dozerz that you may be interested in (the 2011, not the silver/gold).
https://bitcointalk.org/index.php?topic=5376642.0

As far as others who have these coins and may wish to sell them...  Knowing what price you're trying to buy them for could make a big difference in how many responses you get.  I mean, we'd all like to buy Casascius coins at the right price the same as those of us who own them would sell them for the right price.  Knowing what price you're wanting to buy one for would save a lot of time.