To estimate a maximum purchase price for the coin in question, we can analyze the provided data, especially the current grade of the coin (95 S/C-) and the hammer prices from previous auctions.

1. Grade: The coin has a grade of 95, indicating that it is in very good condition. This generally translates to a higher price compared to coins with lower grades.

2. Previous hammer prices: By observing the hammer prices from previous auctions for coins with similar grades, we can see that:
- In 2021, a coin with a grade of 85 was sold for 3300 and 4000 euros.
- In 2021, a coin with a grade of 90 was sold for 3200 euros.
- In 2023, a coin with a grade of 75 was sold for 2500 euros.

3. Price trends: The average hammer price for this particular coin is 3996.15 euros, suggesting that the market is willing to pay close to this price for coins in good condition.

4. Starting price: The starting price of 4500 euros is an indicator that the seller expects a high price, but it does not necessarily mean that it will be reached.

5. Estimation: Given that the grade of the coin is high (95) and considering the previous hammer prices, a reasonable maximum purchase price could be in the range of 5000 to 6000 euros. This is based on the fact that hammer prices for coins of similar grades have reached figures close to these values.

Therefore, an estimated maximum purchase price for this coin could be 5500 euros.