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

1. Coin Condition: The coin to be auctioned has a condition of 80 (MS+). This is an important factor, as coins in better condition tend to reach higher prices.

2. Previous Prices: By observing the hammer prices of coins with similar conditions, we can see that coins with a condition of 80 have had hammer prices that vary, but are generally in a range that can reach up to 70-80 euros in recent auctions.

3. Average Hammer Price: The average hammer price for this coin is 54.22 euros, which gives us an idea of what buyers are willing to pay on average.

4. Auction Trends: The coin has been auctioned 61 times, of which 52 have sold. This indicates a consistent interest in the coin, which can influence the price.

5. Starting and Estimated Prices: The starting price is 25 euros, and the average starting price is 34.57 euros. This suggests that the starting price is relatively low compared to the average hammer price.

Taking all these factors into account, an estimated maximum purchase price for this coin could be around 80-90 euros, considering that the condition is good and there is a price history that supports this estimate. However, it is important to remember that the final price may vary depending on the competition in the auction and the interest of collectors at that time.