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 relatively good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction History:
- The average hammer price for similar coins in the past is 71.38 euros.
- The coin has been auctioned 49 times, of which 40 have resulted in sales. This suggests there is consistent interest in this coin.
- Previous hammer prices for coins with similar conditions (75 and 80) have varied, but there are examples of auctions reaching up to 132 euros for coins in condition 95.

3. Starting Price and Estimates:
- The current starting price is 25 euros, which is quite low compared to the average hammer price.
- The average starting price of 39.88 euros also suggests that the current starting price could be attractive to buyers.

4. Recent Trends: In the most recent auctions, hammer prices have shown a range that could be significant. For example, in a recent auction, a coin with a condition of 70 was sold for 50 euros.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 70 to 90 euros, considering that the condition is good and that interest in the coin appears to be solid. However, since the starting price is 25 euros, it is likely that buyers will be willing to bid beyond this price, especially if there is competition in the auction.

Therefore, an estimated maximum purchase price could be 85 euros.