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 25 (BC), which indicates that it is in quite poor condition. This generally reduces the value of the coin compared to others in better shape.

2. Previous Auction Prices: By looking at previous hammer prices, we can see that prices have varied significantly depending on the condition. For example:
- A coin with a condition of 75 sold for 110 euros.
- Another with a condition of 80 sold for 80 euros.
- A coin with a condition of 70 sold for 180 euros.

3. Average Hammer Price: The average hammer price for similar coins is 243.29 euros, but this includes coins in better conditions.

4. Current Starting Price: The starting price is 80 euros, which can be a good indicator of what is expected to be obtained in this auction.

5. Sales Trends: Of the 16 times it has been auctioned, it has sold on 14 occasions, indicating good demand for this coin, although the current condition may affect interest.

Given that the condition of this coin is quite low (25), and considering the hammer prices of coins in similar conditions, an estimated maximum purchase price could be in the range of 80 to 110 euros. However, since the starting price is 80 euros, a reasonable maximum price could be approximately 100 euros. This would allow for a small premium over the starting price, but also reflects the low condition of the coin.