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 a similar condition (around 75), we can see that auction prices have varied. For example, in recent auctions, coins with a condition of 75 have reached hammer prices of up to 70-80 euros.

3. Average Hammer Price: The average hammer price for this coin is 75.57 euros, which gives us a good reference for what buyers are willing to pay.

4. Starting Price and Average Starting Price: The starting price is 15 euros, and the average starting price is 53.19 euros. This suggests that there is a considerable margin between the starting price and the hammer price.

5. Recent Trends: The coin has been auctioned 205 times in the past, with an 85% sell-through rate, indicating consistent demand.

Based on these factors, an estimated maximum purchase price for this coin could be between 80 and 100 euros, considering that the condition is good and that there is a trend for hammer prices to remain in that range for coins of similar condition.

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