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

1. Current Condition: The coin has a condition of 75 (MBC), which indicates that it is in an acceptable state, but not in the best condition.

2. Previous Prices: By observing the auction prices of coins with a similar condition (75), we can see that they have reached auction prices that vary, but generally range between 220 and 360 euros in recent auctions.

3. Average Hammer Price: The average hammer price for this coin is 406.24 euros, suggesting that, in general, buyers are willing to pay more than the starting price.

4. Recent Trends: In the most recent auctions, hammer prices have been quite high, even for coins with similar conditions. For example, in a recent auction, a coin with a condition of 75 was sold for 360 euros.

5. Starting Price: The starting price is 175 euros, which is relatively low compared to previous hammer prices.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 350 to 400 euros, considering that the condition is an important factor and that hammer prices have been higher in the past.

Therefore, a reasonable maximum purchase price could be 400 euros.