To estimate a maximum purchase price for the coin in question, we can consider several factors based on the provided data:

1. Current Condition: The coin has a condition of 75 (MBC), indicating that it is in fairly good shape, but not the best possible condition.

2. Previous Prices: Looking at previous auction prices for coins with a similar condition (75), we can see that they have varied. For example:
- In previous auctions with a condition of 75, the hammer prices have been 15, 20, 25, 28, 35, and 55 euros.
- The average hammer price for similar conditions seems to be around 25-35 euros.

3. Average Hammer Price: The average hammer price for this particular coin is 32.58 euros, suggesting that, in general, buyers are willing to pay around this amount.

4. Starting Price: The starting price is 25 euros, which is reasonable and aligns with previous hammer prices.

5. Recent Trends: In the most recent auctions, hammer prices have shown a trend of being in the range of 35-60 euros for similar conditions.

Based on these points, an estimated maximum purchase price for this coin could be in the range of 35 to 45 euros. This is based on the current condition, previous hammer prices, and the general market trend.