Based on the data provided, we can observe that the coin in question has had an average auction closing price of 72.54 euros in previous auctions. Additionally, the current condition of the coin is 80 (VF+).

Considering that the starting price for the upcoming auction is 30 euros and the historical average starting price is 61.62 euros, we can assume that the closing price could be above these values.

Given that the condition of the coin is relatively good (80), and considering that in previous auctions it has reached closing prices of up to 140 euros, we could estimate a maximum purchase price around 140 euros, taking into account the upward trend in closing prices and the condition of the coin.

Therefore, my estimation for the maximum purchase price for this coin in the upcoming auction would be around 140 euros.