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), indicating a medium-good quality. This generally translates to a higher price compared to coins of lower condition.

2. Previous Auction Prices: By observing previous auction prices for coins with similar conditions (75-85), we can see that auction prices have varied. For example:
- In recent auctions, coins with a condition of 80 have reached auction prices of up to 150 euros.
- Coins with a condition of 85 have been auctioned for 270 euros.

3. Average Auction Price: The average auction price for this coin is 86.06 euros, providing a reference point.

4. Auction Trends: The coin has been auctioned 106 times, with a high sales percentage (97 out of 106). This suggests a steady demand.

5. Starting Price: The starting price is 70 euros, which may influence the final price, as buyers often consider the starting price when making their bids.

Based on these factors, an estimated maximum purchase price could be between 120 and 150 euros, considering that the condition is good and there are precedents of higher auction prices for coins of similar quality. However, the final price will depend on the competition in the auction and the interest of collectors at that time.