To estimate a maximum purchase price for the coin in question, we can consider several factors:

1. Current Condition: The coin has a condition of 80 (MS+), 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 from previous auctions for coins with similar conditions, we can see that:
- In past auctions, coins with a condition of 80 have reached hammer prices of up to 110 euros.
- The average hammer prices for coins with conditions of 70 and 75 have been in the range of 50 to 90 euros.

3. Average Hammer Price: The average hammer price for this particular coin has been 97.79 euros, which is also a good indicator of the expected value.

4. Starting Price and Average Starting Price: The current starting price is 60 euros, and the average starting price has been 72.31 euros. This suggests that the market is willing to pay more than the starting price.

5. Recent Trends: In the most recent auctions, hammer prices have been in the range of 60 to 110 euros for similar conditions.

Based on these factors, an estimated maximum purchase price for this coin could be around 110 euros, as this is a price that has been reached in previous auctions for coins of similar condition and aligns with the average hammer price. However, it is important to consider that the final price may vary depending on the competition in the auction and the interest of collectors.