Based on the provided data, we can observe that the coin in question has had a starting price in the current auction of 18 euros and is in a conservation grade of 70 (MBC-). Additionally, it has been auctioned in the past 22 times, sold in 20 instances, and not sold in 2 instances.

The average starting price of previous auctions has been 28.14 euros, while the average final price has been 40.7 euros. Regarding the previous prices of this coin, we can see that it has had variations in its starting, estimated, and final values throughout past auctions.

Given that the conservation grade of the coin is 70 (MBC-) and considering the previous prices of similar auctions as well as the average final price, we could estimate a maximum purchase price of around 35-40 euros for this coin in the current auction. It is important to note that this is just an estimate and the final price may vary depending on demand and other factors in the auction.