Based on the provided data, the coin will be auctioned with a starting price of 25 euros and a conservation grade of 25 (BC). In the past, this coin has been auctioned twice, both times it was sold, with an average starting price of 42.5 euros and an average final price of 80 euros.

Additionally, we have information about a previous auction where the coin was sold in 2015 for a starting price of 60 euros, an estimated price of 90 euros, and a final price of 95 euros.

Given that the coin has been sold in the past and its final price was 95 euros in a previous auction, we can estimate that the maximum purchase price could be around 100-110 euros, considering the upward trend in final prices and the interest it has generated in previous auctions.

Therefore, my estimate for the maximum purchase price for this coin in the next auction would be around 100-110 euros.