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

1. Starting Price: 120 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 fairly good shape, but not the best possible condition.
3. Auction History: The coin has been auctioned 2 times in the past, of which it sold once and did not sell once. This suggests that there is interest in the coin, but also that there may be limitations in demand.
4. Previous Prices: In the previous auction, the starting price was 70 euros and it sold for 110 euros. This indicates that there is potential for the coin to reach a higher price in the future, especially if demand is high.

Given that the current starting price is 120 euros and considering the previous hammer price of 110 euros, an estimated maximum purchase price could be in a range that reflects both the interest in the coin and its condition.

Taking all these factors into account, an estimated maximum purchase price could be approximately 100-110 euros. This is based on the previous hammer price and the current condition, suggesting that buyers may be willing to pay a little more than the previous hammer price, but not as much as the current starting price.