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

1. Starting Price: 50 euros.
2. Condition: The coin has a condition rating of 70 (VF-), indicating that it is in relatively good shape, but not the best possible condition.
3. Auction History: The coin has been auctioned 2 times in the past and has sold on both occasions. The previous hammer prices were 60 euros in 2014 and 65 euros in 2017.
4. Average Hammer Price: The average hammer price for this coin is 62.5 euros, which can serve as a reference.
5. Average Starting Price: The average starting price in previous auctions is 56.67 euros.

Given that the coin has a condition rating of 70 and considering the auction price history, an estimated maximum purchase price could be set in a range that reflects both the average hammer price and the current starting price.

Taking all these factors into account, a reasonable maximum purchase price could be approximately 70-75 euros. This is based on the fact that the condition is good and that the price history shows it has reached hammer prices close to this range in the past.