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

1. Condition of the coin: The coin has a condition rating of 95 (EBC+), which indicates that it is in very good condition. This generally translates to a higher value compared to coins with lower conditions.

2. Previous auction prices: By looking at the hammer prices of coins with similar conditions (90-95), we can see that the hammer prices have varied considerably. For example:
- In 2019, a coin with a condition of 90 was sold for 245 euros.
- In 2014, a coin with a condition of 95 was sold for 500 euros.

3. Starting price and average hammer price: The current starting price is 250 euros, and the average hammer price for this coin in the past has been 79.12 euros. However, since the condition of this coin is significantly better than average, we can expect the hammer price to be higher.

4. Market trends: Given that the coin has been auctioned 88 times in the past and has had a good sales percentage (79 out of 88), this suggests that there is consistent interest in this coin.

Based on these factors, an estimated maximum purchase price could be in the range of 400 to 600 euros, considering that the condition is high and there are precedents for sales in that range. However, given the starting price of 250 euros, it is likely that the hammer price will not exceed 500 euros in this specific auction.

Therefore, a reasonable maximum purchase price could be 500 euros.