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

1. Current Condition: The coin has a condition of 75 (MBC), which indicates that it is in relatively good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction History:
- The average hammer price for similar coins is 64.29 euros.
- In the past, coins with similar conditions (75-80) have sold in a price range that varies, but some examples are:
- A coin with a condition of 75 was auctioned for 20 euros (2022-07-07).
- Another with a condition of 80 was auctioned for 30 euros (2023-01-31).
- A coin with a condition of 85 was auctioned for 55 euros (2021-06-22).

3. Starting Price and Estimated Price:
- The starting price is 20 euros, and the average starting price is 44.14 euros. This suggests that the starting price is relatively low compared to the average hammer price.

4. Sales Trends: The coin has been auctioned 58 times, of which 49 have sold, indicating good demand.

Based on these factors, an estimated maximum purchase price could be in the range of 60 to 80 euros, considering that the condition is good and that the price history shows that coins in similar conditions have reached higher prices.

Therefore, a reasonable maximum purchase price could be 70 euros.