Based on the data provided, we can see that the coin in question has had an average auction price of 45.61 euros in previous auctions. Additionally, the current condition of the coin is 90 (EBC).

Considering that the average auction price has been 45.61 euros and that the condition of the coin is quite good (90), we could estimate a maximum purchase price around 50-55 euros. Since the coin will be auctioned in the coming days, it is important to note that the final price may vary depending on the demand at that specific time.

Therefore, an estimated maximum purchase price for this coin in the upcoming auction could be around 50-55 euros.