Based on the provided data, we can observe that the coin in question has a grade of 80 (MBC+), indicating that it is in fairly good condition. Additionally, it has been auctioned three times in the past, with an average selling price of 731.67 euros.

We are also given information about two previous auctions of this same coin. In the first auction, which took place on November 19, 2020, the coin was sold for 15 euros with a grade of 70. In the second auction, held on March 16, 2023, the coin was sold for 2000 euros with a grade of 100.

Considering that the coin is in a grade of 80 (MBC+), and taking into account the previous auction prices as well as the average selling price of 731.67 euros, we could estimate a maximum purchase price of around 1500-1800 euros for this coin in the next auction. It is important to note that the final price may vary depending on the demand at the time of the auction and other external factors.