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 for this coin in the past has been 54.82 euros.
- In previous auctions, hammer prices have varied significantly, with some reaching up to 220 euros in higher conditions (condition rating of 90).
- Most recent auctions with similar conditions (around 75) have had hammer prices ranging between 20 and 60 euros.

3. Starting Price and Average Starting Price:
- The current starting price is 20 euros, and the average starting price in the past has been 23.08 euros.

4. Recent Trends:
- In recent auctions, the hammer price has been in the range of 40 to 61 euros for similar conditions.

Based on this data, an estimated maximum purchase price for this coin, considering its condition and price history, could be in the range of 60 to 80 euros. This is based on the fact that, although the condition is not the highest, the interest in the coin and its price history suggest that it could reach a higher price in a competitive auction.