Based on the provided data, here is an analysis to estimate a maximum purchase price for the coin in question:

1. Starting Price: 80 euros. This is the initial price set for the auction.
2. Condition: The coin has a condition rating of 75 (MBC), indicating that it is in good shape, but not of the highest quality (FDC).
3. Auction History: The coin has been auctioned once in the past but did not sell, which may indicate that interest or demand is not high.
4. Average Hammer Price: There are no data on previous sales, making it difficult to establish a reference price based on past sales.

Given that the coin has a starting price of 80 euros and considering its condition (75), an estimated maximum purchase price could be slightly above the starting price, but not by much, since it has not been successful in previous sales.

Estimated Maximum Purchase Price: It may be reasonable to consider a maximum purchase price between 80 and 100 euros, depending on the interest of bidders in the auction. However, since it has not sold in the past, it is likely that the price will remain closer to the starting price. Therefore, a maximum purchase price of 90 euros could be a prudent estimate.