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

1. 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. Auction History:
- The average hammer price for this coin is 61.36 euros.
- In previous auctions, we have seen hammer prices that varied significantly, with some reaching up to 225 euros in exceptional conditions (such as in 2015).
- Most hammer prices for coins in similar conditions (80 MS+) have been in the range of 40 to 70 euros.

3. Starting Price: The current starting price is 50 euros, which is a good starting point.

4. Recent Trends: In the most recent auctions, hammer prices have been in the range of 40 to 65 euros for coins of similar condition.

Based on these factors, an estimated maximum purchase price could be around 80 euros. This is because, although the average hammer price is 61.36 euros, the good condition of the coin and the history of higher prices suggest that there could be enough interest to reach a higher price. However, it is important to keep in mind that the market can be variable, and collector interest at the time of the auction will also influence the final price.