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 with lower conditions.

2. Starting Price and Average Hammer Price: The starting price is 90 euros, and the average hammer price in previous auctions is 113.22 euros. This suggests that, on average, similar coins have sold for above their starting price.

3. Sales History: The coin has been auctioned 31 times, of which it has sold 28 times. This indicates good demand and a history of successful sales.

4. Previous Prices: By looking at previous hammer prices for coins with similar conditions, we can see that they have reached hammer prices that varied, but some have exceeded 100 euros. For example, in 2024, a coin with a condition of 85 sold for 190 euros.

5. Recent Trends: In the most recent auctions, hammer prices have shown an increase, which could indicate an upward trend in the value of these coins.

Based on these factors, an estimated maximum purchase price could be in the range of 130 to 150 euros. This is based on the history of hammer prices and the current condition of the coin. However, since the starting price is 90 euros, it is likely that the final hammer price will be closer to this upper range, especially if there is interest in the auction.