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

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

2. Historical Prices: By looking at previous auction prices, we can see that in past auctions, coins with a similar condition (95) have reached auction prices that vary, but generally have sold in a range of 350 to 500 euros. For example:
- In 2019, a coin with a condition of 95 was auctioned for 350 euros.
- In 2020, a coin with a condition of 100 was auctioned for 500 euros.
- In 2021, coins with a condition of 95 were auctioned for 420 and 395 euros.

3. Starting Price and Average Hammer Price: The current starting price is 350 euros, and the average hammer price in previous auctions is 350.63 euros. This suggests that the starting price is reasonable and that there is a good chance it will sell for a similar or higher price.

4. Auction Trends: The coin has been auctioned 27 times, of which 24 have sold. This indicates good demand and consistent interest in the coin.

Based on these factors, an estimated maximum purchase price could be in the range of 400 to 500 euros, considering that the condition is high and there are precedents for sales in that range. A price of 450 euros could be a reasonable target, as it aligns with previous hammer prices and the condition of the coin.