Based on the data provided, we can observe that the coin in question had a starting price of 15 euros in the current auction, with a conservation grade of 70 (MBC-). Additionally, it has been auctioned in the past on several occasions, with varying starting and final prices.

The average starting price of this coin in previous auctions has been 34 euros, while the average final price has been 44.8 euros. We can also see that in the last recorded auction, the coin was sold for an estimated price of 20 euros.

Taking into consideration these data, as well as the conservation grade of the coin and the previous auction prices, we could estimate a maximum purchase price around 50 euros. This estimation is based on the fact that the average final price has been higher than the average starting price, and considering that the coin has sold in most of the previous auctions.

It is important to note that the final auction price may vary depending on the demand at the time of the auction and other external factors.