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

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

2. Historical Data:
- In 2019, a coin with a condition of 95 sold for 860 euros.
- In 2023, a coin with a condition of 80 did not sell, but had a starting price of 400 euros.
- In 2024, another coin with a condition of 80 sold for 1100 euros.

3. Average Hammer Price: The average hammer price for this coin is 853.33 euros, which gives us an idea of the market value.

4. Starting Price: The current starting price is 200 euros, which is quite low compared to previous hammer prices.

5. Price Trends: The average starting price of 450 euros and the fact that all previous auctions have resulted in sales indicate that there is a consistent interest in this coin.

Given that the current condition of the coin is 75 (VF), which is lower than the conditions of 80 and 95 of the previously auctioned coins, and considering the average hammer price and the starting price, an estimated maximum purchase price could be in the range of 600 to 800 euros.

Therefore, a reasonable estimated maximum purchase price for this coin could be 750 euros.