To estimate a maximum purchase price for the coin in question, we can consider several factors based on the provided data:

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. Current Starting Price and Previous Prices: The current starting price is 1500 euros, and the average hammer price in previous auctions has been 2237.83 euros. This suggests that the hammer price is usually significantly higher than the starting price.

3. Sales History: The coin has been sold in 24 out of the last 32 auctions, indicating good demand. Additionally, the average hammer price in previous auctions for coins with similar condition (85) has been approximately 1400 to 1800 euros, with some auctions reaching up to 3200 euros in exceptional cases.

4. Recent Trends: In the most recent auctions, hammer prices have shown an upward trend, especially for coins in good condition.

Based on these factors, an estimated maximum purchase price could be between 2500 and 3000 euros. This is based on the average hammer price and the condition of the coin, as well as the price trend in recent auctions.

Therefore, a reasonable maximum purchase price could be approximately 2800 euros.