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 fairly good shape, but not the best possible condition.

2. Auction History:
- The average hammer price in previous auctions is 33.47 euros.
- Starting prices have varied, with some hammer prices in similar conditions (75 and 80) reaching up to 59.78 euros in the past.

3. Price Trends:
- In previous auctions, starting prices have ranged from 12.12 euros to 78.93 euros, but the most relevant hammer prices for similar conditions have been in the range of 20 to 59.78 euros.

4. Current Starting Price: The starting price is 15 euros, suggesting that there is room for the hammer price to be significantly higher.

5. Sale Expectations: Given that there have been 19 previous auctions and 9 sales, there is moderate interest in this coin, which may influence competition during the auction.

Based on these factors, an estimated maximum purchase price could be in the range of 50 to 60 euros, considering that the condition is good and there is a history of hammer prices in that range for similar conditions. However, given the starting price of 15 euros, it is possible that the actual hammer price may be lower, but this range provides a reasonable target for an interested buyer.