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

1. 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 with lower conditions.

2. Previous Prices: By looking at previous auction prices for coins with similar conditions (95 and close), we can see that the highest auction price was 650 euros in 2020 for a coin with the same condition. There was also an auction for 1010 euros for a coin with a condition of 95 in 2014.

3. Average Auction Price: The average auction price for this coin is 231.98 euros, which provides a reference point.

4. Starting Price: The starting price is 300 euros, indicating that the seller expects a reasonable price for the coin.

5. Market Trends: Since the coin has been auctioned 54 times and has had a sell-through rate of 88.89% (48 out of 54), this suggests there is consistent interest in this coin.

Based on these factors, an estimated maximum purchase price could be between 600 and 800 euros, considering that the condition is high and there are precedents for auctions in that range. However, since the starting price is 300 euros, it is likely that the final auction price will not significantly exceed this range unless there is strong competition among bidders.

Therefore, a reasonable maximum purchase price could be 700 euros.