To estimate a maximum purchase price for the coin in question, we can consider several factors:

1. Condition: The coin has a condition rating of 85 (ebc-), which indicates that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction history:
- The average hammer price in previous auctions is 61.95 euros.
- The average starting price is 55.09 euros.
- In past auctions, the hammer price has varied, with a maximum of 150 euros in a 2022 auction, although this may be an exceptional case.

3. Sales trends: The coin has been auctioned 12 times, of which it has sold 10 times. This indicates good demand and consistent interest in the coin.

4. Current starting price: The starting price is 65 euros, which is slightly higher than the average starting price in the past, but may be reasonable given the condition.

Taking all these factors into account, an estimated maximum purchase price could be in the range of 80 to 100 euros. This is based on the hammer price history and the condition of the coin. A price of 90 euros could be a reasonable target, considering it is slightly higher than the previous average hammer price and reflects the good condition of the coin.