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 value compared to coins with lower conditions.

2. Auction History:
- The average starting price for similar coins is 72.81 euros, and the average final price is 77.58 euros.
- In the past, this coin has had starting prices ranging from 50 to 176.78 euros, with final prices reaching up to 200 euros on some occasions.

3. Sales Trends: Out of the 17 times it has been auctioned, 12 have sold, indicating a reasonable sell-through rate. This suggests there is interest in the coin.

4. Current Starting Price: The starting price is 60 euros, which is relatively low compared to the average starting and final prices of similar coins.

5. Previous Estimates: In previous auctions, estimated prices have varied, but generally, final prices have been in the range of 60 to 100 euros for similar conditions.

Taking all these factors into account, an estimated maximum purchase price could be around 90-100 euros. This is based on the condition, interest in the coin, and previous final prices. However, it is important to remember that the final price may vary depending on competition in the auction and other market factors at the time of sale.