Some fact checking is in order here to help a newbie avoid getting ripped off.
First, there are a total of 2,178 redeemed 2011 series 1 and 2 Casascius coins, so they are hardly "very rare" (
https://casasciustracker.com/status).
Second, the current premium on a 2011 1 BTC funded Casascius is not more than 0.1 BTC depending on the condition and demand. The value of that coin at the moment would be no more than ~$53,590 USD. Nobody with a 2011 1 BTC funded Casascius listed on eBay is going to fetch $200k USD from a buyer in their right state of mind. That would be robbery.