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

1. 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 in previous auctions is 26.38 euros.
- The last auction with a similar condition (95) had a hammer price that has not been specified, but the starting price was 15 euros and the estimated price was 25 euros.
- In previous auctions, coins with a condition of 100 have sold for up to 75 euros.

3. Starting price and estimates:
- The current starting price is 20 euros, which is a good starting point.
- The average starting price in the past has been 16.15 euros, suggesting that the current starting price is reasonable.

4. Sales trends: Out of the 19 times it has been auctioned, 14 have been sold, indicating good demand.

Taking all these factors into account, an estimated maximum purchase price could be in the range of 40 to 60 euros. This is based on the good condition of the coin and the hammer price history in previous auctions. A price of 50 euros could be a reasonable target, as it falls in the middle of this range and reflects the quality of the coin.