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

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. Auction History:
- The average hammer price in previous auctions is 61.06 euros.
- The coin has been auctioned 20 times, of which it has sold 18 times, indicating good demand.
- Previous hammer prices for coins with similar conditions (85) have ranged from 40 to 95 euros.

3. Starting Price and Average Starting Price:
- The current starting price is 30 euros, and the average starting price in the past has been 39.5 euros.

4. Price Trends:
- In recent auctions, hammer prices for coins with similar conditions have ranged from 40 to 85 euros.

Based on these factors, an estimated maximum purchase price could be in the range of 75 to 90 euros, considering that the condition is good and there is a history of hammer prices that supports this estimate.

Therefore, a reasonable estimated maximum purchase price for this coin could be 85 euros.