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 80 (MBC+), indicating that it is in relatively good shape. This suggests that its value should be above that of coins with lower conditions.

2. Previous Auction Prices: By observing the hammer prices of coins with similar conditions (around 80), we can see that the hammer prices have varied. For example:
- In 2018, a coin with a condition of 80 was auctioned for a hammer price of 200 euros.
- In 2022, another coin with a condition of 80 was sold for 95 euros.

3. Average Hammer Price: The average hammer price for this coin is 233.42 euros, indicating that, in general, coins of this reference tend to reach higher prices.

4. Starting Price and Previous Hammer Prices: The current starting price is 40 euros, which is significantly lower than previous hammer prices. This could indicate a good buying opportunity.

5. Auction Trends: Given that there have been 58 previous auctions and 52 sales, demand appears to be high, which may influence the hammer price.

Based on these factors, an estimated maximum purchase price could be in the range of 200 to 300 euros, considering that the average hammer price is 233.42 euros and there are examples of previous sales exceeding 200 euros.

Therefore, a reasonable maximum purchase price could be 250 euros.