To estimate a maximum purchase price for the coin in question, we can 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 45.8 euros.
- The last auction with a known hammer price was 60 euros for a coin with a condition of 80.
- In previous auctions, coins with similar conditions (80-90) have reached hammer prices ranging from 60 to 95 euros.

3. Starting Price and Estimated Price:
- The current starting price is 40 euros, and the estimated price is 50 euros. This suggests that the market is willing to pay more than the starting price.

4. Sales Trends: The coin has been auctioned 43 times, of which 38 have been successful sales. This indicates good demand in the market.

Based on these factors, an estimated maximum purchase price could be in the range of 70 to 90 euros, considering that the condition is good and that the hammer price history for similar coins supports this estimate.

Therefore, a reasonable maximum purchase price could be 85 euros.