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 of 75 (MBC), indicating that it is in quite good shape.

2. Auction History:
- The average hammer price for coins of similar condition (75) in the past has been approximately 45-85 euros, with some higher hammer prices for coins in better conditions.
- In previous auctions, coins with a condition of 75 have had hammer prices that varied, but the highest was 85 euros.

3. Starting Price and Average Hammer Price:
- The current starting price is 40 euros, and the average hammer price in the past has been 74.71 euros. This suggests that the hammer price could be in a similar range or slightly higher.

4. Recent Trends:
- In the most recent auctions, the hammer price has been around 45-85 euros for coins of similar condition.

Based on these points, an estimated maximum purchase price for this coin could be in the range of 80 to 90 euros. This is based on the historical hammer prices for coins of similar condition and the current state of the coin. However, it is important to consider the competition in the auction and the current demand, which could influence the final price.