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 the best possible condition.

2. Auction History:
- The average hammer price in previous auctions is 69.96 euros.
- The coin has been auctioned 16 times, of which it has sold 10 times, indicating a reasonable sell-through rate.
- Previous hammer prices for coins with similar conditions (75) have varied, but there are examples of hammer prices around 66.83 euros and 163.76 euros for a condition of 75.

3. Starting Price: The starting price is 25 euros, which is quite low compared to the average hammer price.

4. Price Trends: Given that the average starting price is 61.15 euros, and considering that the condition of the coin is 75, it is reasonable to think that the hammer price could be in a range above the starting price.

Based on these factors, an estimated maximum purchase price could be positioned between the average hammer price and a bit more, given that the condition is good.

Estimated Maximum Purchase Price:

We could estimate a maximum purchase price around 80-90 euros. This is based on the auction price history and the current condition of the coin.