Based on the data provided, we can observe that the coin in question has had an average starting price of 40.4 euros in previous auctions, with an average closing price of 42.11 euros. The conservation of the coin is described as 80 (MBC+), indicating that it is in fairly good condition.

When analyzing the previous prices of this coin in past auctions, we can see that it has had a wide price range, from 18 euros to 110 euros. The highest estimated price was 150 euros, while the lowest estimated price was 10 euros.

Given that the coin will be auctioned with a starting price of 30 euros and considering its price history, conservation, and demand in previous auctions, we could estimate a maximum purchase price around 50-60 euros. This is considering that the coin is in fairly good conservation condition and has had closing prices higher than the starting price in most previous auctions.