To estimate a maximum purchase price for the coin in question, we will consider several factors:

1. Current Condition: The coin has a condition of 75 (MBC), which indicates that it is in quite good shape. This is relevant because coins in better condition tend to fetch higher prices at auctions.

2. Auction History:
- The average hammer price for similar coins is 847.25 euros.
- In previous auctions, coins with a similar condition (75) have reached hammer prices of 460 euros (2022) and 650 euros (2022).
- The last auction of a coin with a condition of 75 had a hammer price of 400 euros (2024).

3. Starting Price: The starting price is 250 euros, which may influence bidder interest.

4. Price Trends: Observing the hammer prices of coins with similar conditions, it seems that the price range for coins in MBC condition can fluctuate between 400 and 650 euros, depending on demand and other market factors.

Based on this data, an estimated maximum purchase price for this coin could be around 600-700 euros, given that it is a price that has been reached in previous auctions for coins in similar conditions and considering the interest it might generate in the current auction.

Therefore, a reasonable maximum purchase price could be 700 euros.