Based on the data provided, we can observe that the coin in question had a starting price of 9 euros in the most recent auction, with a conservation grade of 30 (BC+). Additionally, it has been auctioned 11 times in the past, with an average starting price of 40.64 euros and an average closing price of 58.27 euros.

When analyzing the previous prices of this coin in past auctions, we can see that it has had significant variations in its starting, estimated, and closing prices over the years. The conservation grade of the coin has also varied, ranging from 30 to 80.

Taking into consideration this data, as well as the trend of previous prices, we could estimate a maximum purchase price for this coin at around 70-80 euros, considering its conservation grade and price history. It is important to note that the final price in an auction can vary depending on demand and other market factors at the time of the auction.