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, with a conservation grade of 70 (MBC-). Additionally, it has been auctioned in the past on several occasions, with closing prices ranging between 35 and 110 euros.

The average starting price of this coin in previous auctions has been 28.62 euros, while the average closing price has been 45.6 euros. In past auctions, it has been sold 11 times and not sold 3 times.

Considering the previous prices of this coin, as well as its current conservation grade, we could estimate a maximum purchase price around 50 euros. Given that the highest closing price was 110 euros in the past, and considering the conservation of the coin, an estimated maximum purchase price of 50 euros seems reasonable.

It is important to note that the final auction price will depend on various factors, such as demand at that specific moment, competition from other bidders, and buyers' perception of the coin's value at that time.