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 (MBC), which indicates that it is in fairly good shape, but not of the highest quality (FDC).

2. Historical Prices: By looking at previous auction prices for coins with similar conditions (75 and 80), we can see that auction prices have varied. For example:
- In 2020, a coin with a condition of 75 was auctioned for 60 euros.
- In 2018, a coin with a condition of 75 was auctioned for 65 euros.
- In 2022, a coin with a condition of 75 was auctioned for 60 euros.

3. Average Auction Price: The average auction price for this coin is 111.61 euros, suggesting that there is a higher potential selling price, but this may be influenced by coins in better condition.

4. Starting Price and Average Starting Price: The starting price is 50 euros, and the average starting price is 61.59 euros. This indicates that the market is willing to start bidding from these values.

5. Sales Trends: The coin has been auctioned 86 times, of which 74 have been successful sales. This suggests that there is consistent interest in this coin.

Based on these factors, an estimated maximum purchase price could be between 80 and 100 euros. This is based on the fact that, although the condition is not the highest, there is a price history that suggests buyers are willing to pay more for coins in similar conditions.

Therefore, a reasonable maximum purchase price could be 90 euros.