Yes, I too believe that the main problem with this idea will be to gain trust in your buyers.
I personally like the idea; a wallet in which you know the public key so you can send BTC to that address and check your balance, and can only be spent if you really need the money and are willing to throw the coin/wallet away. It would serve as a savings account, or even a piggy bank!
If it is meant to be a disposable coin/wallet (after it has been spent), I believe it should be affordable. I think you could probably sell it for $10 because of its novelty value, but if you're charging more I personally would not want it.
A way you could make more from this is offer the coin (as a physical wallet) for $10 with one satoshi on it, and give the option of buying a coin with a balance of .5BTC, 1BTC, 1.5BTC, etc. You could charge an extra percentage or two above market value and earn a good amount of BTC over time
Can't wait to see what it looks like.