Based on the data provided, we can observe that the coin in question has had a starting price in the current auction of 25 euros, with a conservation grade of 70 (MBC-). Additionally, it has been auctioned in the past on several occasions, with varying starting and final prices.

The average starting price of this coin in previous auctions has been 51.06 euros, while the average final price has been 64.79 euros. The conservation grade of the coin in previous auctions has ranged between 30 and 85.

Given that the current conservation grade of the coin is 70 (MBC-), and considering the starting and final prices of previous auctions, as well as the estimated price trends, we could estimate a maximum purchase price for this coin at around 90 euros.

It is important to note that the final auction price may vary depending on factors such as demand at the time of the auction and the interest of potential buyers.