Based on the data provided, we can observe that the coin has had an average auction closing price of 99.14 euros in previous auctions. Additionally, the current condition of the coin is 70 (VF-).

Considering that the current condition of the coin is 70 and the average auction closing price in previous auctions has been 99.14 euros, we could estimate a maximum purchase price of around 110 euros. Since the condition of the coin is not excellent, it is prudent not to exceed the historical average auction closing price too much.

Therefore, an estimated maximum purchase price for this coin in the upcoming auction could be around 110 euros.