$28 is ok, I guess. The Comex price is about $21.50 today. The condition doesn't matter, those are not collector coins. As long as it is 1 ounce its fine.
To the silver rounds I can't say much, we don't really do them here. It would add 19% VAT if it is a non currency silver piece. Also, I can imagine it would be harder to sell, since people have more trust in officially minted coins.