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

1. Condition: The coin to be auctioned has a condition of 95 (EBC+), which indicates that it is in very good shape. This is a positive factor that can increase its value.

2. Previous Prices: By looking at the hammer prices from previous auctions for coins with similar conditions, we can see that:
- In 2022, a coin with a condition of 95 was sold for 3600 euros.
- In 2024, another coin with a condition of 95 was estimated at 4500 euros and sold for 3800 euros.

3. Average Hammer Price: The average hammer price for this particular coin has been 1406.79 euros, but this includes coins of different conditions.

4. Starting Price: The starting price of 2000 euros is a good starting point, but given that the condition is high, it is likely that the hammer price will be significantly higher.

5. Auction Trends: Since the coin has been auctioned 15 times and all have sold, this indicates a consistent interest in the coin, which can increase its value at auction.

Taking all these factors into account, an estimated maximum purchase price could be between 3500 and 4000 euros, considering that the condition is high and there are precedents for sales in that range for similar coins.

Therefore, a reasonable maximum purchase price could be 4000 euros.