Based on the provided data, we can observe that the coin in question has had a starting price in this auction of 25 euros, with a grade of 80 (MBC+). Additionally, it has been auctioned in the past on several occasions, with closing prices ranging between 12 and 100 euros.

The average closing price of this coin in previous auctions has been 43.82 euros, while the average starting price has been 42.42 euros. This indicates that the coin tends to increase in value during auctions.

Considering the good grade of the coin (80 MBC+) and the fact that it has reached prices of up to 100 euros in previous auctions, we could estimate a maximum purchase price in this auction to be around 110-120 euros. Given that the estimated price in this auction is 25 euros, it is possible that the final closing price will exceed this amount, but it is difficult to predict exactly by how much.

In summary, an estimated maximum purchase price for this coin in the current auction could be around 110-120 euros, considering its price history and grade.