Based on the data provided, we can see that the coin in question has had an average starting price of 30.3 euros in previous auctions, with an average closing price of 50.95 euros. The condition of the coin is described as '80 (MBC+)'.

Additionally, several previous prices of this coin have been recorded in past auctions, with condition values ranging between 75 and 90. The highest recorded closing price was 140 euros.

Given that the coin is in a condition of 80 (MBC+), and considering the previous prices and the average closing price, as well as the fact that it has been auctioned 15 times in the past, we can estimate a maximum purchase price for this coin at around 70-80 euros. This range is based on the condition of the coin and the previous prices recorded in similar auctions.