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

1. Coin Condition: The coin has a condition rating of 80 (MS+), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Previous Auction Prices: By observing the hammer prices of coins with similar conditions (around 80), we can see that the hammer prices have varied. For example, in previous auctions, coins with a condition of 80 have reached hammer prices of up to 60 euros.

3. Average Hammer Price: The average hammer price for this coin is 100.98 euros, suggesting that there is a higher selling potential, especially if demand is strong.

4. Starting Price and Recent Hammer Prices: The starting price is 25 euros, which is relatively low compared to previous hammer prices. This may attract more bidders, potentially increasing the final price.

5. Market Trends: Given that it has been auctioned 131 times and sold 116 times, there is consistent interest in this coin, which may indicate that its value will hold or increase.

Based on these factors, an estimated maximum purchase price for this coin could be between 80 and 120 euros, considering that the condition is good and there is a history of hammer prices supporting this estimate. However, given the starting price of 25 euros, it is likely that the final price will be closer to the lower end of this range unless there is significant competition in the auction.