To estimate a maximum purchase price for the coin in question, we can consider several factors based on the provided data:

1. Current Condition: The coin has a condition rating of 75 (MBC), indicating that it is in fairly good shape, but not among the best qualities.

2. Auction History:
- The average hammer price for similar coins in the past has been 112.42 euros.
- The coin has been auctioned 36 times, of which it has sold 33 times, indicating good demand.
- Previous hammer prices for coins with a similar condition (75) have varied, but there are examples of auctions reaching up to 70-75 euros in recent sales.

3. Starting Price and Average Starting Price:
- The current starting price is 30 euros, which is relatively low compared to the average hammer price.
- The average starting price for similar coins is 87.71 euros.

4. Recent Trends: In the most recent auctions, hammer prices for coins with a condition of 75 have been in the range of 65 to 75 euros.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 70 to 90 euros. This is because, although the starting price is low, the demand and price history suggest it could reach a higher price at auction.

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