I buy them all. Here is my offer for you today.

You pay escrow fee.

Casascius 2012 Silver Gilt Ten (10 BTC) Ungraded for 17.35 BTC   (First owner)  11BTC
Casascius 2012 Silver Ten (10 BTC) Ungraded for 17 BTC   (First owner & GPG-signed by Casascius!) 11BTC
Casascius 2012 S2 Nickel Five (5 BTC) 1Cspg1ZT Ungraded for 9.4 BTC (First owner) 5.2BTC
Casascius 2012 S1 (Error) Nickel Five (5 BTC)  Ungraded for 8.8 BTC 5.2BTC
Casascius 2013 Silver Single (1 BTC) MS-69 for 2.55 BTC 2.25BTC
Casascius 2013 Brass Single (1 BTC) Ungraded 1.3 BTC  1.1BTC

Total 35 and change BTC

I cover shipping.