Based on the data provided, we can see that the coin in question has had an average auction closing price of 69.34 euros in previous auctions. Additionally, the condition of the coin on this occasion is estimated to be 70 (VF+).

Considering that the condition of the coin is relatively good and the average auction closing price in previous auctions has been 69.34 euros, we could estimate a maximum purchase price around that value or slightly higher, taking into account the upward trend in closing prices.

Therefore, an estimated maximum purchase price for this coin in the next auction could be around 70-75 euros. It is important to note that this is just an estimate and the final price could vary depending on demand and other factors in the auction.