Based on the data provided, we can observe that the coin in question has a grade of 80 (MBC+), with a starting price in the upcoming auction of 30 euros. Additionally, it has been auctioned in the past 20 times, sold in 16 instances, and not sold in 4 instances.
The average starting price in previous auctions has been 40.7 euros, while the average final price has been 55.27 euros. Regarding the previous prices of this coin, we can see that it has had variations in its starting, estimated, and final values over the years.
Given that the coin's condition is good (80 MBC+), and considering the previous prices of similar auctions, as well as the current starting price and average starting and final prices, we could estimate a maximum purchase price around 60-70 euros. It is important to consider that the final auction price may vary depending on the demand at the auction and other factors that may influence buyers' decisions.