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 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. Starting Price and Average Hammer Price: The starting price is 360 euros, and the average hammer price in previous auctions is 319.83 euros. This suggests that the starting price is slightly higher than the average of what has sold in the past.

3. Sales History: The coin has been auctioned 37 times, of which 36 have been sold. This indicates good demand and consistent interest in the coin.

4. Previous Prices: Looking at previous hammer prices for coins with similar conditions (around 80-90), prices have varied, but there are examples of auctions reaching up to 600 euros in optimal conditions.

5. Recent Trends: In the most recent auctions, hammer prices have shown an increase, especially for coins in good condition. For example, in March 2023, a coin with a condition rating of 95 was sold for 600 euros.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 400 to 450 euros, considering that the starting price is 360 euros and that the condition is quite good. This also takes into account the trend of increasing hammer prices in recent auctions.