To estimate a maximum purchase price for the coin in question, let's consider the following factors:

1. Starting Price: 60 euros. This is the initial price of the auction.
2. Condition: The coin has a condition rating of 75 (MBC), indicating that it is in fairly good shape, but not the best possible condition.
3. Historical Data: In the past, this coin was auctioned with a starting price of 110 euros and sold for 110 euros. This suggests that, despite a higher starting price, the interest in the coin was sufficient to reach the final price.
4. Average Starting and Final Prices: The average starting price is 85 euros and the average final price is 110 euros. This indicates that, generally, coins of this reference tend to sell for above their starting price.

Given that the coin has a condition rating of 75 and considering the historical and average prices, an estimated maximum purchase price could be in a range between the average final price and a bit more, given that the condition is good.

Therefore, an estimated maximum purchase price could be around 120-130 euros. This is based on the good condition and the demonstrated interest in previous auctions.