Based on the provided data, we can observe that the coin in question has had an average auction price of 311.62 euros in the past. Additionally, its current condition is 75 (MBC).

Considering the coin's previous prices and its evolution in past auctions, as well as its current condition, we could estimate a maximum purchase price around 400-450 euros. Given that the average auction price has been 311.62 euros and there have been auctions where it has sold for over 400 euros, a range of 400-450 euros could be a reasonable estimate for the maximum purchase price on this occasion.