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 of the highest quality (FDC).

2. Auction History:
- The average hammer price for similar coins in the past has been 21.68 euros.
- The coin has been auctioned 60 times, of which 41 resulted in sales. This indicates a consistent interest in the coin.
- Previous hammer prices for coins with similar conditions (around 75) have varied, but there are examples of auctions reaching up to 30 euros.

3. Starting Price and Average Starting Price:
- The starting price is 15 euros, and the average starting price is 18.35 euros. This suggests that the starting price is reasonable and could attract bidders.

4. Recent Trends:
- In the most recent auctions, hammer prices have been in the range of 20 to 30 euros for similar conditions.

Based on these factors, an estimated maximum purchase price for this coin could be between 25 and 30 euros. This is because, although the average hammer price is 21.68 euros, the good condition and interest in the coin suggest that it could reach a higher price at auction.

Therefore, a reasonable maximum purchase price could be 30 euros.