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

1. Condition: The coin being 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. Previous auction prices: By observing the hammer prices of coins with similar conditions (95 and 90), we can see that the hammer prices have varied, but they have been in a range that suggests a coin in EBC+ condition could reach prices close to 400-500 euros.

3. Starting price and average prices: The starting price of 450 euros is a good indicator, and the average hammer price of 338.97 euros suggests that, although the starting price is higher, interest in the coin may lead to a higher hammer price.

4. Auction trends: In recent auctions, hammer prices for coins of similar condition have ranged from 371 to 555 euros.

Based on these factors, an estimated maximum purchase price for this coin could be between 500 and 600 euros, considering that the condition is high and there is potential interest in the coin. However, since the starting price is 450 euros, it is likely that the hammer price will not significantly exceed this amount unless there is active competition among bidders.

Therefore, a reasonable estimated maximum purchase price could be 550 euros.