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 47.23 euros.
- In recent auctions, the hammer prices for coins with similar condition (95) have been 60, 70, 90, and 50 euros.

3. Starting price: The current starting price is 15 euros, which is relatively low compared to previous hammer prices.

4. Price trends: Observing the hammer prices from previous auctions, it seems there is a trend for coins in condition 95 to sell for above 50 euros, and in some cases, even more.

Based on these factors, an estimated maximum purchase price could be in the range of 70 to 90 euros, considering that the highest hammer price in the past for coins in similar condition has been 90 euros.

Therefore, a reasonable estimated maximum purchase price could be 85 euros.