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

1. Coin Condition: The coin has a condition rating of 85 (MBC+/EBC-), 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 a similar condition (85), we can see that they have reached hammer prices that vary considerably. For example:
- In previous auctions, coins with a condition of 85 have reached hammer prices of up to 240 euros (as seen in the auction on 2019-03-14).
- There are also examples of coins with a condition of 80 that have sold for lower prices, but still, the price range is quite broad.

3. Average Hammer Price: The average hammer price for this coin is 128.83 euros, which provides a good reference point.

4. Starting Price and Average Starting Price: The starting price is 75 euros, and the average starting price is 81.02 euros. This suggests that the market is willing to pay more than the starting price on many occasions.

5. Recent Trends: The price trend in recent auctions is also important. If similar coins have been increasing in price, this could indicate a rise in demand.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 150 to 200 euros. This range takes into account the condition, previous hammer prices, and market interest. However, it is important to remember that the final price may vary depending on competition in the auction and other market factors at the time of the auction.