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

1. Coin Condition: The coin has a condition rating of 80 (MBC+), 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 41.35 euros.
- In previous auctions, we have seen hammer prices that vary significantly, but there are examples of sales in the range of 90 to 150 euros for coins with similar or better conditions.

3. Starting Price and Previous Prices:
- The current starting price is 25 euros, which is relatively low compared to the average hammer price.
- The average starting price in the past has been 29.09 euros, suggesting that the current starting price is competitive.

4. Price Trends:
- In recent auctions, coins with similar conditions have reached hammer prices exceeding 50 euros, and some have reached 90 euros or more.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 70 to 90 euros. This is based on the hammer price history and the coin's condition, which suggests that collectors would be willing to pay a higher price for a coin in good condition.