Based on the data provided, we can observe that the coin in question has had an average auction closing price of 73.53 euros in previous auctions. Additionally, its condition has been described as 70 (MBC-), indicating that it is in a fairly acceptable condition.

Considering that the starting price for the next auction is 25 euros and the average closing price has been 73.53 euros, we could estimate a maximum purchase price around 80-85 euros, taking into account the coin's condition and price history.

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.