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

1. Condition: The coin 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 in lower conditions.

2. Previous auction prices: By looking at previous hammer prices for coins with a similar condition (95 or 100), we can see that the hammer prices have varied, but generally, they have been in a range of 200 to 400 euros. For example:
- In December 2020, a coin with a condition of 95 was sold for 305 euros.
- In July 2020, a coin with a condition of 100 was sold for 400 euros.
- In March 2023, a coin with a condition of 95 was sold for 320 euros.

3. Starting price and average hammer price: The current starting price is 250 euros, and the average hammer price in previous auctions is 253.48 euros. This suggests that the hammer price could be in a similar range or slightly higher.

4. Recent trends: In the most recent auctions, hammer prices have been in the range of 300 to 320 euros for coins of similar condition.

Based on these factors, an estimated maximum purchase price for this coin could be between 320 and 350 euros, considering that collector interest may drive the price up a bit more at auction. Therefore, a reasonable maximum purchase price could be 350 euros.