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

1. Coin 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. Auction History: By looking at previous hammer prices for coins with a similar condition (85), we can see that the hammer prices have varied. For example, in past auctions, coins with a condition of 85 have reached hammer prices of up to 60 euros.

3. Average Hammer Price: The average hammer price for this coin is 51.7 euros, which is also a good indicator of the expected value.

4. Starting Price and Previous Prices: The current starting price is 30 euros, and the average starting price is 36.6 euros. This suggests that the market is willing to pay more than the starting price.

5. Recent Trends: In the most recent auctions, hammer prices have shown a trend of increasing, especially for coins in good condition.

Based on these factors, an estimated maximum purchase price for this coin could be between 70 and 90 euros, considering that the condition is good and there is a history of hammer prices that supports this estimate. However, since the market can be volatile, it is advisable to keep an eye on the auction and adjust the bid accordingly.