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

1. Coin Condition: The coin to be auctioned has a condition rating of 95 (EBC+), indicating that it is in very good shape. This is a positive factor that can increase its value.

2. Auction History:
- The coin has been auctioned 9 times in the past, of which it has sold 8 times. This indicates good demand.
- The average hammer price in previous auctions is 296.25 euros, which is a good indicator of market value.

3. Previous Auction Prices:
- Hammer prices for coins with a similar condition (95) have varied, but there are examples of auctions reaching up to 300 euros.
- The current starting price is 100 euros, which is relatively low compared to the average hammer price.

4. Price Trends:
- In previous auctions, hammer prices have shown a considerable range, with some reaching up to 600 euros in estimated future auctions.

Based on these factors, an estimated maximum purchase price could be set in a range between 300 and 400 euros, considering that the average hammer price is 296.25 euros and that the coin's condition is high.

Therefore, a reasonable maximum purchase price could be 350 euros. This allows for a margin for competition in the auction, given the price history and the good condition of the coin.