To estimate a maximum purchase price for the coin in question, let's consider several factors:

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

2. Starting Price: The starting price is 300 euros, which is a good starting point.

3. Auction History:
- The average hammer price in previous auctions for coins with a similar condition (95) has been approximately 269.58 euros.
- However, in recent auctions, we have seen hammer prices exceeding 300 euros, such as in the auction on 2023-03-16, where the hammer price was 360 euros.

4. Recent Trends: In the most recent auctions, hammer prices have shown an upward trend, reaching up to 520 euros in a scheduled future auction.

5. Supply and Demand: The coin has been auctioned 68 times, with a high sales percentage (65 out of 68). This suggests that there is a consistent demand for this coin.

Taking all these factors into account, an estimated maximum purchase price could be between 360 and 400 euros, considering that the hammer price in recent auctions has exceeded 300 euros and that the coin's condition is high.

Therefore, a reasonable maximum purchase price could be 400 euros.