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

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

2. Auction History:
- The average hammer price for similar coins has been 65.64 euros.
- In previous auctions, hammer prices have varied, but there are examples of sales reaching up to 95 euros (as seen in the auction on 2024-09-19).

3. Starting Price and Average Starting Price:
- The current starting price is 25 euros, which is below the average starting price of 43.6 euros. This suggests that there is potential for the hammer price to be higher.

4. Sales Trends: The coin has been sold in 13 out of 15 auctions, indicating good demand.

5. Comparison with Previous Prices:
- In past auctions, the hammer price has ranged from 15 to 250 euros, depending on the condition and other factors. However, the most recent and relevant prices are more indicative of the current trend.

Based on these factors, an estimated maximum purchase price could be set in a range between 70 and 90 euros, considering that the condition is good and that the hammer price history suggests it could reach higher figures.

Therefore, a reasonable maximum purchase price could be 85 euros.