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 for this coin in the past has been 112.52 euros.
- Previous auctions with similar conditions (90 and 85) have had hammer prices that varied, but some have reached significant prices, such as 315.39 euros in an auction with a condition of 90.

3. Starting Price and Average Starting Price:
- The current starting price is 75 euros, and the average starting price in the past has been 70.57 euros. This suggests that the current starting price is reasonable and could attract bidders.

4. Sales Trends: The coin has been sold in 23 out of 34 auctions, indicating a consistent interest in the coin.

Based on these factors, an estimated maximum purchase price could be in the range of 120 to 150 euros, considering that the condition is good and that the auction price history suggests buyers are willing to pay more for coins in similar conditions.

Therefore, an estimated maximum purchase price could be 135 euros.