Based on the data provided, we can observe that the coin in question has had an average auction closing price of 27.34 euros in previous auctions. Additionally, the condition of this coin is rated at 95 (UNC), which is quite good.

Considering that the starting price for the upcoming auction is 18 euros and that the estimated closing price has ranged between 16 and 80 euros in previous auctions, we could estimate a maximum purchase price around 80 euros, taking into account the upward trend in closing prices.

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