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

1. Coin Condition: The coin has a condition rating of 80 (MS+), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Previous Auction Prices: By observing the auction prices of coins with similar conditions (around 80-85), we can see that the auction prices have varied. For example, in previous auctions, coins with a condition of 80 have reached hammer prices of up to 90-160 euros.

3. Average Hammer Price: The average hammer price for this coin is 107.29 euros, which provides a good reference point.

4. Auction Trends: The coin has been auctioned 69 times, with a high sales percentage (66 out of 69). This suggests that there is consistent interest in this coin, which may increase its value.

5. Starting Price and Average Starting Price: The current starting price is 30 euros, and the average starting price is 54.55 euros. This indicates 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 between 150 and 200 euros, considering that the condition is good and there is a history of hammer prices that supports this estimate. However, it is important to stay alert to the dynamics of the auction and the competition from other bidders.