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

1. Coin Condition: The coin to be auctioned has a condition rating of 80 (MBC+), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Previous Auction Prices: By looking at the hammer prices of coins with similar conditions (70-85), we can see that the hammer prices have varied, but generally, they have been in a range of 125 to 340 euros.

3. Average Hammer Price: The average hammer price for this coin is 246.75 euros, which provides a good reference point.

4. Starting Price: The starting price of 225 euros is an indicator of what is expected to be obtained at the auction, but it does not necessarily reflect the final hammer price.

5. Recent Trends: In the most recent auctions, we have seen hammer prices exceeding the starting price, especially for coins in good condition. For example, in the auction on 2023-03-22, a coin with a condition of 80 was hammered at 340 euros.

Taking all these factors into account, an estimated maximum purchase price for this coin could be around 300-350 euros. This is based on the trend of hammer prices for coins of similar condition and the interest that this particular coin may generate.