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, with a grade of 70 (MBC-). Additionally, it has been auctioned in the past 18 times, sold in 16 instances, and not sold in 2 instances.

The average starting price in previous auctions has been 49.5 euros, while the average final price has been 76.67 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 current 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 around 90-100 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.