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

1. Coin Condition: The coin has a condition rating of 95 (S/C-), indicating that it is in very good shape. This generally increases its value compared to coins with lower conditions.

2. Auction History:
- The average hammer price for this coin in the past has been 22.95 euros.
- In previous auctions, hammer prices of up to 85 euros have been reached for coins with similar condition (100) and 40 euros for coins with a condition of 95.

3. Starting Price and Estimates:
- The current starting price is 15 euros, which is slightly higher than the average starting price of 12.94 euros.
- The estimated price for this auction is 25 euros, suggesting that moderate interest is expected.

4. Sales Trends: The coin has been sold in 66 out of the 69 previous auctions, indicating good demand.

Based on these factors, a reasonable maximum purchase price could be in the range of 40 to 60 euros, considering that the condition is high and there have been previous auctions with higher hammer prices. However, since the starting price is 15 euros and the estimated price is 25 euros, a maximum purchase price of 50 euros could be a prudent estimate, allowing for some margin for competition in the auction.