Based on the data provided, we can observe that the coin in question has had an average auction closing price of 44.97 euros in previous auctions. Additionally, its condition has been described as '70 (MBC-)', indicating that it is in fairly good condition.

Considering that the starting price for the upcoming auction is 30 euros and the average closing price has been 44.97 euros, we can estimate a maximum purchase price around 45-50 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 stay alert during the auction to adjust the offer accordingly.