Based on the data provided, we can observe that the coin in question has had a starting price in the current auction of 18 euros and is in a conservation grade of 75 (MBC). Additionally, it has been auctioned in the past on several occasions, with final prices ranging between 18 and 110 euros.

The average final price of this coin in previous auctions has been 44 euros, with an average starting price of 30.34 euros. Considering that the current conservation grade is 75 (MBC), and that in the past it has reached prices of up to 110 euros in better conditions, we could estimate a maximum purchase price for this coin in the current auction.

Given that the starting price is 18 euros and taking into account the conservation grade and historical prices, we could consider an estimated maximum purchase price of around 60-70 euros for this coin in the current auction. It is important to note that this is just an estimate and the final price will depend on demand and other factors in the auction.