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

1. Current Condition: The coin has a condition rating of 85 (ebc-). This is an important factor, as coins in better condition tend to reach higher prices.

2. Auction History:
- The average hammer price in previous auctions is 1322.61 euros.
- The last auction with a hammer price was 2600 euros for a coin with a condition rating of 95, indicating that the price can vary significantly based on condition.
- In previous auctions, coins with a similar condition (85) have reached hammer prices ranging from 806 to 1300 euros.

3. Starting Price and Estimated Price:
- The current starting price is 1500 euros, and the estimated price is 2000 euros. This suggests that the seller has expectations of a higher price, but it may also indicate that the market is willing to pay more.

4. Market Trends: Since the coin has sold in 23 of the last 24 auctions, there is consistent demand. This may influence the final price.

Based on these factors, an estimated maximum purchase price could be in the range of 1800 to 2200 euros, considering that the highest recent hammer price was 2600 euros for a coin in better condition. However, given that the condition of this coin is lower, a more conservative price of 1800 euros may be more realistic, while 2200 euros could be the upper limit if there is active competition in the auction.