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 70 (MS-). This is an important factor, as coins in better condition tend to reach higher prices.

2. Previous Auction Prices: By looking at previous auction prices for coins with similar conditions, we can see that:
- In past auctions, coins with a condition of 70 have reached hammer prices of up to 130 euros (for example, in the auction on 2024-05-27).
- The average hammer price for coins with similar conditions seems to be in the range of 70 to 130 euros.

3. Average Hammer Price: The average hammer price for this coin is 86.06 euros, which can also serve as a reference.

4. Auction Trends: The coin has been auctioned 106 times, of which it has sold 100 times. This indicates good demand and a history of successful sales.

5. Starting Price: The starting price is 40 euros, suggesting that the seller expects a reasonable price, but the hammer price could be significantly higher.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 120 to 150 euros, considering that the condition is good and there is a history of hammer prices that supports this estimate. However, it is important to keep in mind that the final price may vary depending on the competition in the auction and the interest of collectors.