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

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

2. Starting Price and Average Hammer Price: The starting price is 700 euros, and the average hammer price in previous auctions is 673.02 euros. This suggests that the starting price is reasonable and could attract buyers.

3. Sales History: The coin has been auctioned 79 times, of which it has sold 68 times. This indicates good demand and a history of successful sales.

4. Previous Prices: By looking at previous hammer prices for coins with a similar condition (85), we can see that they have reached hammer prices of up to 950 euros in recent auctions. For example, in the auction on March 14, 2024, a coin with a condition of 85 was hammered at 950 euros.

5. Recent Trends: In the most recent auctions, hammer prices have shown an upward trend, which could indicate an increase in demand or in the coin's value.

Based on these factors, an estimated maximum purchase price for this coin could be between 800 and 950 euros, considering that the starting price is 700 euros and there is a history of hammer prices that supports this estimate.

Therefore, a reasonable maximum purchase price could be 950 euros.