What kind of coins are they? (Brass, silver, silver gilt) What denomination? Can you share pictures?
They will sell for at least a 20% premium over face value...could be higher for more rare mintages.
Keep in mind that now these coins have Bitcoin cash attached to them, which (today) totals $750 per 1 Bitcoin. You should be sure to include this BCC value into the face value over which you expect to receive for a sale.
I may be personally interest. But you can also post an auction in the
Collectibles board, which is where most Casascius coin lovers hang out.