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

1. Current 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 45.18 euros.
- In previous auctions, hammer prices have varied, but there are examples of sales that reached up to 200 euros (although this may be an exceptional case).
- Most hammer prices for coins with similar conditions (80-85) have been in the range of 40 to 57 euros.

3. Starting Price: The starting price is 25 euros, suggesting that the seller expects a reasonable price, but not necessarily the maximum.

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

5. Comparison with Previous Prices:
- In recent auctions, coins with similar conditions have reached hammer prices of 40 to 57 euros.
- The most recent auction with a condition of 80 had a hammer price of 40 euros.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 50 to 70 euros, considering that the condition is good and there is a history of hammer prices that supports this estimate.

Therefore, a reasonable maximum purchase price could be 65 euros.