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

1. Starting Price: 3000 euros. This is the initial price set for the auction.
2. Condition: The coin has a condition rating of 95 (S/C-), indicating that it is in very good shape. This generally increases its value.
3. Auction History:
- In the December 2021 auction, the coin was estimated at 1000 euros and sold for 600 euros, with a condition rating of 80.
- In the December 2024 auction, a starting price of 1500 euros was set, an estimated price of 3000 euros, and it sold for 2400 euros, with a condition rating of 95.

4. Average Prices: The average starting price is 2250 euros and the average selling price is 1500 euros.

Given that the condition of the current coin is high (95), and considering the selling price of 2400 euros in the previous auction with the same condition, we can infer that the value of this coin could be in a similar or slightly higher range.

Taking all these factors into account, an estimated maximum purchase price could be between 2400 and 3000 euros, making it reasonable to consider a maximum purchase price of approximately 2500 euros. This is based on the sales history and the current condition of the coin.