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 in previous auctions is 72.3 euros.
- The coin has been auctioned 33 times, of which it has sold 27 times, indicating good demand.
- Previous hammer prices for coins with a similar condition (75) have ranged from 35 to 140 euros, with a highest hammer price of 140 euros for a condition of 85.

3. Starting Price and Average Starting Price:
- The current starting price is 40 euros, which is below the average starting price of 55.91 euros. This suggests that there is a buying opportunity at a relatively low price.

4. Recent Trends: In the most recent auctions, hammer prices have been in the range of 45 to 70 euros for similar conditions.

Based on these factors, an estimated maximum purchase price could be around 80-90 euros. This is based on the historical hammer prices for similar conditions and the fact that the coin is in an acceptable state of preservation. However, since the starting price is 40 euros, it may be possible to acquire it for a price below this range, depending on the competition in the auction.