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 75 (MBC), indicating that it is in fairly good shape, but not among the best qualities (FDC).

2. Historical Data:
- The average hammer price for coins with a similar condition (75) in the past has been approximately 100-130 euros, based on previous auctions.
- In past auctions, we have seen hammer prices that varied significantly, but those closest to the current condition are relevant. For example, in a 2022 auction, a coin with a condition of 75 was sold for 55 euros, and in another auction in 2024, a coin with a condition of 75 was sold for 80 euros.

3. Starting Price and Previous Hammer Prices:
- The current starting price is 40 euros, which is relatively low compared to the average hammer price of 177.71 euros. This suggests that there is potential for a higher hammer price.

4. Auction Trends: The coin has been auctioned 24 times, with an 87.5% sell-through rate, indicating good demand.

Based on these factors, an estimated maximum purchase price could be between 100 and 130 euros, considering that the condition is good and there is a history of hammer prices that supports this estimate. However, since the starting price is 40 euros, some bidders may try to acquire it at a lower price, which could influence the final price.

Therefore, a reasonable maximum purchase price could be 120 euros.