Based on the provided data, we can observe that the coin in question had a starting price of 18 euros in the most recent auction, with a conservation value of 30 (BC+). Additionally, it has been auctioned a total of 22 times in the past, being sold in 21 instances and not sold in one.

The average starting price of previous auctions has been 34.5 euros, while the average closing price has been 49.76 euros. Regarding the previous prices of this coin, it has had starting values ranging from 1 euro to 110 euros, with estimated prices ranging from 20 euros to 150 euros.

Taking all these data into consideration, and considering that the coin will be auctioned soon, we could estimate a maximum purchase price around 90-100 euros, taking into account the price history and demand for this particular coin. It is important to note that the conservation value also plays an important role in determining the final price.