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

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

2. Auction History:
- The average hammer price for similar coins has been 324.6 euros.
- In previous auctions, coins with a similar condition (95) have reached hammer prices of up to 650 euros (as seen in the auction on January 31, 2023).

3. Starting Price and Average Starting Price:
- The current starting price is 300 euros, which is slightly higher than the average starting price of 221.9 euros. This may indicate an expectation of greater interest in this auction.

4. Recent Trends: Recent auctions have shown an increase in hammer prices, especially for coins in good condition.

Based on these factors, an estimated maximum purchase price could be in the range of 500 to 650 euros, considering that the highest hammer price in the past for a coin in similar condition was 650 euros. However, since the starting price is 300 euros, a reasonable purchase price could be around 500 euros, which represents a potential profit margin for the seller and an attractive price for the buyer.

Therefore, an estimated maximum purchase price could be approximately 550 euros.