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

1. Coin Condition: The coin to be auctioned has a condition rating of 95 (S/C-), indicating that it is in very good shape. 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 indicates a consistent interest in the coin.
- The average hammer price from previous auctions is 31.8 euros, which can serve as a benchmark.

3. Previous Auction Prices:
- In past auctions, hammer prices have varied, with a maximum of 110 euros in a 2021 auction for a coin with a condition of 85.
- In the most recent auction (2023), although the hammer price is not indicated, the starting price was 15 euros with an estimated price of 25 euros.

4. Current Starting Price: The starting price for the current auction is 40 euros, suggesting that significant interest in the coin is expected.

5. Price Trends: Given that the coin's condition is high and considering the price history, it is reasonable to assume that the hammer price could be above the historical average.

Taking all these factors into account, an estimated maximum purchase price could be in the range of 70 to 90 euros, considering the high condition and demonstrated interest in previous auctions. This also allows for some margin for competition in the auction.