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

1. Condition: The coin has a condition rating of 75 (MBC), indicating that it is in a medium-low state. This generally affects the price, as coins in better condition tend to fetch higher prices.

2. Starting price and previous prices: The current starting price is 75 euros. In previous auctions, the average hammer price has been 178.76 euros, suggesting there is significant potential for the hammer price to be higher than the starting price.

3. Price trends: By observing the hammer prices of coins with a similar condition (75), we can see that they have reached hammer prices that vary, but some have reached 80 euros in recent auctions. However, there are also examples of coins with similar conditions that have reached higher prices, such as 110 euros.

4. Demand and supply: The coin has been auctioned 91 times in the past, with an 84% sell-through rate, indicating good demand. Additionally, it will be auctioned again shortly, which may increase interest.

5. Analysis of previous prices: The hammer prices of coins with a condition of 75 have varied, but the range seems to be between 60 and 110 euros in the most recent auctions.

Based on these factors, an estimated maximum purchase price for this coin could be between 100 and 120 euros. This is based on the analysis of previous prices and the current condition of the coin. However, since the average hammer price is 178.76 euros, it is possible that some buyers may be willing to pay more, especially if there is interest in the auction.

Therefore, a reasonable maximum purchase price could be 120 euros.