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 similar coins in the past has been 65.45 euros.
- In previous auctions, coins with a similar condition (75) have reached hammer prices that varied, but there are examples where they sold for between 30 and 54 euros.

3. Starting Price: The starting price is 30 euros, which may influence bidder interest.

4. Price Trends: Observing the hammer prices of coins with similar conditions, it seems that the price range can fluctuate between 30 and 60 euros, with some exceptional cases reaching up to 100 euros for higher conditions.

Given all this, an estimated maximum purchase price for this coin could be around 70-80 euros, considering that bidder interest may drive the price above the average, especially if there is competition in the auction. However, it is important to keep in mind that the final price will depend on the demand at the time of the auction.