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

1. Current Condition: The coin has a condition of 85 (ebc-), which indicates that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Current Starting Price and Previous Prices: The current starting price is 1300 euros. The average hammer price in previous auctions is 1388.82 euros, suggesting that buyers are willing to pay a bit more than the starting price on average.

3. Price Trends: Looking at previous hammer prices, there are examples of prices that have exceeded 1500 euros, especially for coins with similar or better conditions. For instance, in 2018, a coin with a condition of 95 was sold for 1500 euros, and in 2021, a coin with a condition of 90 was sold for 1700 euros.

4. Comparison with Prices of Similar Condition: In the most recent auction of 2024, a coin with a condition of 75 was sold for 1950 euros, indicating that there is a market willing to pay high prices for coins in good condition.

Taking all these factors into account, an estimated maximum purchase price for the coin with a condition of 85 could be in the range of 1600 to 1800 euros. This is based on the trend of previous hammer prices and the current condition of the coin.

Therefore, a reasonable maximum purchase price could be 1700 euros.