Based on the data provided, we can observe that the coin in question has shown variability in its auction closing prices in previous auctions. The starting price for the upcoming auction is 12 euros, and the coin's condition is graded at 70 (MBC-).

The average closing price in previous auctions has been 72.05 euros, with an average starting price of 52.75 euros. Considering the coin's condition is 70 (MBC-) and it has had previous closing prices ranging between 14 and 220 euros, we could estimate a maximum purchase price of around 100 euros for this coin in the upcoming auction.

It is important to note that the final auction price may vary depending on factors such as demand at that specific time, competition from other bidders, and interest in the particular coin.