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 fairly good shape, but it is not the best possible condition.

2. Historical Prices: By looking at previous auction prices for coins with similar conditions (75 and 80), we can see that the hammer price has varied. For example:
- In previous auctions, coins with a condition of 75 have reached hammer prices of 30 to 54 euros.
- Coins with a condition of 80 have reached hammer prices of up to 120 euros.

3. Average Hammer Price: The average hammer price for this coin is 65.45 euros, suggesting that, in general, buyers are willing to pay around this amount.

4. Starting Price: The starting price is 30 euros, which is relatively low compared to the average hammer price.

5. Recent Trends: In the most recent auctions, hammer prices have shown a trend of being higher, especially for coins in good condition.

Based on these factors, an estimated maximum purchase price for this coin could be between 70 and 90 euros. This is because, although the condition is not the highest, the price history and recent trend suggest that buyers might be willing to pay a bit more than the average, especially if demand is high at the auction.

Therefore, a reasonable maximum purchase price could be 80 euros.