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

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

2. Previous Auction Prices: By observing the hammer prices of coins with a similar condition (95) in previous auctions, we can see that the hammer prices have varied but have reached figures close to 400 euros on several occasions. For example, in the auction on 2023-03-16, a coin with a condition of 95 was sold for 445 euros.

3. Average Hammer Price: The average hammer price for this coin is 301.26 euros, but given the high condition, it is reasonable to expect that the hammer price will be above this average.

4. Starting Price: The starting price of 400 euros is a good indicator of what is expected to be obtained in the auction. However, since the starting price does not always translate into the final hammer price, it is important to consider the price history.

5. Recent Trends: In the most recent auctions, hammer prices for coins of similar condition have been in the range of 400 to 500 euros.

Based on these factors, an estimated maximum purchase price for this coin could be between 450 and 500 euros, considering that the condition is high and there is a recent trend for hammer prices to exceed 400 euros.

Therefore, a reasonable estimated maximum purchase price would be approximately 480 euros.