Based on the provided data, we can observe that the coin in question has had a starting price in this auction of 18 euros, with a grade of 30 (BC+). Additionally, it has been auctioned in the past seven times, always selling, with an average starting price of 73.29 euros and an average closing price of 133.57 euros.

When analyzing the previous prices of this coin, we can see that it has had a fairly wide price range in previous auctions, with estimated values ranging from 40 euros to 125 euros, and closing prices ranging from 70 euros to 320 euros.

Given that the grade of the coin is 30 (BC+), and considering the previous prices and the starting price in this auction, as well as the fact that it has sold in all previous auctions, we could estimate a maximum purchase price around 150-180 euros. It is important to note that this is just an estimate and the final price may vary depending on the demand in the current auction.