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 75 (MBC), indicating a fairly good condition, but not excellent. This may influence the price, as coins in better condition tend to reach higher prices.

2. Current Listing Price and Previous Prices: The current listing price is 1500 euros. The average hammer price in previous auctions is 1552.74 euros, suggesting that similar coins have reached prices close to this value.

3. Sales History: The coin has been sold 20 times, indicating a consistent interest in it. Additionally, the highest recorded hammer price in the past was 3200 euros, although this was for a coin in better condition (90).

4. Price Trends: Observing the hammer prices from previous auctions, there is a trend of increasing prices, especially in recent years. For example, in 2023, a similar coin was sold for 3200 euros.

5. Comparison with Similar Conditions: In previous auctions, coins with condition ratings of 75 have had hammer prices ranging from 900 to 1300 euros, but there are also examples of higher prices depending on demand and the auction context.

Taking all these factors into account, an estimated maximum purchase price for this coin could be around 1800 euros. This value reflects a balance between the current condition, historical interest in the coin, and recent market trends.