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

1. Coin Condition: The coin to be auctioned has a condition of 95 (EBC+), which indicates that it is in very good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Price History: By looking at previous auction prices for coins with similar conditions (95 and 100), we can see that auction prices have varied. For example:
- In 2021, a coin with a condition of 95 was auctioned for 45 euros.
- In 2022, another coin with a condition of 95 was auctioned for 25 euros.
- In 2023, a coin with a condition of 95 was auctioned for 45 euros.

3. Average Auction Price: The average auction price for this coin is 17.15 euros, but given the high condition, we can expect the actual auction price to be above this average.

4. Starting Price and Previous Estimates: The starting price is 15 euros, and the average starting price in previous auctions has been 12.15 euros. However, given the auction history and the condition, it is reasonable to expect that the auction price will be above these values.

Taking all these factors into account, an estimated maximum purchase price for this coin could be between 40 and 50 euros, considering that the condition is high and there are precedents for auctions in that range. However, it is important to keep in mind that the final price will depend on the competition in the auction and the interest of other collectors.