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

1. Current Condition: The coin has a condition rating of 75 (MBC), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction History:
- The average hammer price for similar coins in MBC condition has been approximately 45 euros.
- In previous auctions, hammer prices for coins with similar conditions have varied, but there are examples of sales reaching up to 90 euros (as seen in the auction on 2020-09-17).

3. Starting Price and Average Starting Price: The current starting price is 25 euros, which is quite low compared to the average starting price of 47.45 euros. This suggests that there is potential for the hammer price to be significantly higher.

4. Recent Trends: In the most recent auctions, hammer prices have been in the range of 25 to 35 euros for coins with a condition of 70, indicating that interest in well-preserved coins remains strong.

5. Auction Expectations: Given that it will be auctioned in the coming days and considering historical interest, it is reasonable to expect that the hammer price will be above the starting price.

Based on these factors, an estimated maximum purchase price for this coin could be between 60 and 90 euros, considering that the condition is good and there is a price history that supports this estimate. A price of 75 euros could be a reasonable target, as it aligns with the average hammer price for coins in similar conditions.