Based on the data provided, we can observe that the coin in question has had an average auction price of 100.67 euros in previous auctions. Additionally, the condition of the coin has been described as '70 (MBC-)'.

Considering that the condition of the coin is relatively good and the average auction price has been 100.67 euros, we could estimate a maximum purchase price around that value or slightly higher, taking into account that the coin will be auctioned in the coming days.

Therefore, an estimated maximum purchase price for this coin could be around 105 to 110 euros. It is important to note that the final auction price will depend on several factors, such as demand at that specific time, competition from other bidders, and the buyer's willingness to pay for the coin in question.