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

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

2. Previous Prices:
- In the November 2022 auction, a coin with the same condition (95) was estimated at 40 euros and did not sell, suggesting that the final price could have been higher if there had been interest.
- In the February 2023 auction, the same condition was estimated at 30 euros and sold for 26 euros, indicating that interest may have slightly decreased.
- In the December 2024 auction, a coin with a condition of 90 was estimated at 50 euros and sold for 30 euros, which also suggests that the price may vary depending on demand.

3. Average Hammer Price: The average hammer price for similar coins is 36.67 euros, which can serve as a good indicator of market value.

4. Starting Price and Average Starting Price: The current starting price is 18 euros, which is relatively low compared to previous hammer prices. The average starting price is 25.14 euros.

Considering all these factors, an estimated maximum purchase price could be in the range of 40 to 50 euros, given that the condition is high and there is a history of hammer prices suggesting interest in that range. However, since interest may fluctuate, a price of 45 euros could be a reasonable target for a maximum bid.