Based on the data provided, we can observe that the coin in question has had a starting price in this auction of 25 euros, with a conservation grade of 70 (MBC-). Additionally, it has been auctioned in the past on several occasions, with closing prices ranging between 20 and 300 euros.

The average starting price in previous auctions has been 69.2 euros, while the average closing price has been 100.63 euros. The coin has been sold in 90% of the previous auctions.

Considering this data, as well as the previous prices of the coin, we can estimate a maximum purchase price for this coin in the current auction. Since the highest closing price was 300 euros, and considering the conservation grade of the coin is 70 (MBC-), we could estimate a maximum purchase price around 250 euros.

It is important to note that the final auction price may vary depending on the demand at that specific moment, so it is advisable to monitor the auction's progress to adjust the offer accordingly.