Based on the provided data, we can observe that the coin in question has had an average starting price in past auctions of 27.4 euros and an average closing price of 58.89 euros. Additionally, it has been auctioned a total of 10 times in the past, with a current conservation value of 30 (BC+).

When analyzing the previous prices of this coin, we can see that it has had variations in the estimated and closing prices in previous auctions. For example, in the auction on 2021-06-03, an estimated price of 50 euros was set and it closed at that same value, with a conservation grade of 70. In contrast, in the auction on 2022-10-17, an estimated price of 70 euros was set and it closed at 80 euros, with a conservation grade of 70.

Given that the current conservation of the coin is 30 (BC+), and considering the previous prices and auction history, we could estimate a maximum purchase price of around 80-90 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 auction and other factors that may influence the valuation of the coin.