Based on the data provided, we can observe that the coin in question had a starting price of 90 euros in this auction, with a conservation grade of 70 (MBC-). Additionally, it has been auctioned in the past on four occasions, being sold each time. The average starting price in previous auctions has been 111 euros, while the average final price has been 252.5 euros.

Analyzing the previous prices of this coin, we can see that it has had a fairly wide price range, with estimates ranging from 95 euros to 350 euros. The highest final price was 400 euros in a past auction.

Given that the coin is in a conservation grade of 70 (MBC-) and considering the history of previous prices as well as the average final price, we could estimate a maximum purchase price of around 300 euros for this auction. It is important to note that the final price may vary depending on the demand at the auction and other external factors.