Based on the data provided, we can observe that the coin in question has had an average auction closing price of 107.8 euros in previous auctions. Additionally, the current condition of the coin is 70 (VF-).

Considering that the condition of the coin is relatively good (70), and that the average auction closing price in previous auctions has been 107.8 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 110-120 euros. It is important to note that this is just an estimate and the final price will depend on various factors, such as demand at the auction and competition from other bidders.