To estimate a maximum purchase price for the coin that is going to be auctioned, we can consider several factors based on the provided data:

1. Coin Condition: The coin in question 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. Previous Prices: By observing the hammer prices of coins with similar conditions (85-95), we can see that the hammer prices have varied. For example, in previous auctions, coins with a condition of 85 have reached hammer prices of up to 270 euros.

3. Average Hammer Price: The average hammer price for this coin is 104.05 euros, which gives us a good reference for what buyers are willing to pay.

4. Auction Trends: The coin has been auctioned 137 times, of which 122 have been sold. This indicates a consistent interest in the coin, which may influence the price.

5. Starting Prices and Estimates: The starting price is 60 euros, and the average starting price is 69.23 euros. However, given that the condition is good and there is interest in the coin, it is reasonable to expect that the hammer price will be significantly higher.

Taking all these factors into account, an estimated maximum purchase price for this coin could be between 200 and 300 euros, considering that the condition is good and there is a history of hammer prices that supports this estimate.