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

1. Current Condition: The coin has a condition rating of 95 (EF+), indicating that it is in very good shape. This generally increases its value compared to coins in lower conditions.

2. Starting Price and Hammer Price: The current starting price is 400 euros, and the average hammer price in previous auctions is 327 euros. This suggests that the starting price is aligned with market expectations but may be a bit high compared to the average hammer price.

3. Auction History: The coin has been auctioned 3 times and has sold in all of them. This indicates that there is demand for this coin, which can positively influence its price.

4. Previous Prices: In previous auctions, the hammer prices were 320 euros (with a condition of 90) and 111 euros (with a condition of 75). Given that the current condition is better, it is reasonable to expect that the hammer price will be higher than 320 euros.

5. Market Trends: Since the average starting price is 241.67 euros and the average hammer price is 327 euros, we can infer that the market is willing to pay more for coins in better condition.

Taking all these factors into account, an estimated maximum purchase price could be between 350 and 400 euros, considering that the condition is high and there is a history of successful sales. However, since the starting price is 400 euros, it is possible that the hammer price will not exceed this value, so a reasonable maximum purchase price could be approximately 375 euros.