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

1. Current Condition: The coin has a condition rating of 75 (MBC), indicating that it is in good condition. This generally translates to a higher price compared to coins with lower conditions.

2. Auction History:
- The coin has been auctioned 6 times in the past, of which it has sold 5 times. This suggests that there is consistent interest in the coin.
- The average hammer price in previous auctions is 41 euros, which can serve as a good indicator of market value.

3. Previous Auction Prices:
- Previous hammer prices varied, but the highest was 65 euros in 2018, while the lowest was 15 euros in 2017. However, the most recent prices (2020 and 2022) show a range of 40 to 65 euros, indicating that interest and value have increased in recent years.

4. Starting Price and Estimates:
- The current starting price is 40 euros, and the average starting price in previous auctions is 33.13 euros. This suggests that the current starting price is reasonable and aligned with market interest.

5. Future Projections:
- Given that there are 2 auctions scheduled in the coming days, this could increase competition and potentially the hammer price.

Based on these factors, an estimated maximum purchase price could be in the range of 60 to 70 euros. This is based on the hammer price history, current condition, and interest in the coin. Therefore, a reasonable maximum purchase price could be 65 euros.