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 has a condition rating of 75 (MBC), indicating that it is in quite 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 67.61 euros.
- Previous auctions of coins with a similar condition (75) have had hammer prices that varied, but some have reached up to 96 euros (as seen in the auction on December 14, 2020).

3. Starting Prices and Hammer Prices:
- The current starting price is 40 euros, which is relatively low compared to the average hammer price.
- The average starting price in the past has been 45.66 euros, suggesting that the current starting price is competitive.

4. Sales Trends: The coin has been sold in 59 out of 68 auctions, indicating good demand and a history of successful sales.

Based on these factors, an estimated maximum purchase price could be in the range of 80 to 100 euros, considering that the condition is good and there is a history of hammer prices that supports this estimate. A price of 90 euros could be a reasonable target, as it falls in the middle of this range and aligns with previous hammer prices for coins of similar condition.