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

1. Starting price: 60 euros.
2. Condition: The coin has a condition rating of 70 (VF-), indicating that it is in relatively good shape.
3. Auction history: It has been auctioned once in the past and sold on that occasion, suggesting there is interest in the coin.
4. Average hammer price: 75 euros, which is the average price it has sold for in the past.

Given that the condition is good and the average hammer price is higher than the starting price, we could estimate that the maximum purchase price could be in a range above the starting price, but not too far above the average hammer price.

Taking these factors into account, an estimated maximum purchase price could be around 80-85 euros. This reflects interest in the coin, its good condition, and the sales history.