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

1. Current Condition: The coin has a condition of 75 (MBC), which indicates that it is in fairly good shape, but not the best possible condition.

2. Previous Auction Prices: By looking at the hammer prices from previous auctions, we can see that:
- In 2022, a coin with a condition of 95 sold for 1700 and 2000 euros.
- In 2021, a coin with a condition of 85 sold for 1300 euros.
- In 2020, a coin with a condition of 80 sold for 1400 euros.

3. Starting Price and Average Hammer Price: The current starting price is 1600 euros, and the average hammer price in previous auctions is 1167.9 euros. This suggests that the starting price is relatively high compared to the historical average.

4. Price Trends: Throughout the auctions, prices have shown an upward trend, especially for coins in better condition. However, the hammer price can vary depending on demand at the time of the auction.

Given that the condition of the coin is 75 (MBC) and considering the hammer prices of coins with similar conditions, an estimated maximum purchase price could be between 1300 and 1500 euros. This is based on the fact that, although the starting price is 1600 euros, the average hammer price is lower and the condition is not the highest.

Therefore, a reasonable estimated maximum purchase price could be 1500 euros.