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

1. Coin Condition: The coin to be auctioned has a condition rating of 95 (S/C-), indicating that it is in very good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction History:
- The average hammer price in previous auctions for this coin is 238.47 euros.
- In past auctions, we have seen hammer prices that varied, with some reaching up to 320 euros under similar conditions.

3. Starting Price: The starting price is 250 euros, suggesting that the seller has expectations of a relatively high hammer price.

4. Price Trends: Looking at previous hammer prices, there are examples of coins with similar conditions that have sold for 270 euros and 320 euros. This suggests that there is a market willing to pay higher prices for coins in good condition.

Based on these factors, an estimated maximum purchase price could be in the range of 270 to 320 euros. Given that the starting price is 250 euros, a reasonable maximum price to consider could be approximately 300 euros. This is based on the trend of previous prices and the good condition of the coin.