To estimate a maximum purchase price for the coin in question, we will 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 15.98 euros.
- In past auctions, we have seen hammer prices that vary significantly, with a maximum price of 130 euros for a coin in condition 100, and other hammer prices ranging from 10 to 50 euros for conditions similar to the current one (95).

3. Starting price and estimates:
- The current starting price is 15 euros, which is a good starting point.
- The estimated price for this auction is 25 euros, suggesting that bidders may be willing to pay more than the starting price.

4. Sales trends: The coin has been sold in 70% of the auctions it has participated in, indicating relatively strong demand.

Based on these factors, an estimated maximum purchase price could be in the range of 30 to 50 euros. This is based on the hammer price history for coins of similar condition and the demonstrated interest in previous auctions.

Therefore, a reasonable maximum purchase price could be 40 euros.