Based on the data provided, we can observe that the coin has had an average auction closing price of 67.95 euros in previous auctions. Additionally, the condition of this coin is rated at 80 (MBC+).

Considering that the starting price of the upcoming auction is 30 euros and the estimated average closing price is 67.95 euros, we can estimate a maximum purchase price around 70-75 euros, taking into account the condition of the coin and previous closing prices.

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 pay attention to the auction to adjust the offer accordingly.