Based on the data provided, we can observe that the coin has had an average starting price of 12 euros in previous auctions, with an average closing price of 19 euros. The condition of the coin on this occasion is 85 (ebc-), indicating that it is in good condition.

Considering the coin's previous prices and its current condition, as well as the fact that it has been auctioned 34 times in the past, we can estimate a maximum purchase price around 25-30 euros. Given that the average closing price has been 19 euros, and taking into account the condition and demand for this coin, a maximum purchase price of 25-30 euros seems reasonable.

It is important to note that the final auction price may vary depending on the competition from other bidders and external factors at the time of the auction.