Based on the data provided, we can observe that the coin in question had a starting price of 300 euros in the most recent auction, with a conservation value of 80 (MBC+). Additionally, it has been auctioned 13 times in the past, being sold in 9 instances and not sold in 4 instances.

The average starting price of previous auctions has been 264.23 euros, while the average closing price has been 299 euros. Previous prices of this coin have varied, with estimates ranging from 225 euros to 700 euros, and closing prices ranging from 135 euros to 420 euros.

Given that the conservation of the coin is 80 (MBC+), and considering the previous prices and trends of past auctions, we could estimate a maximum purchase price of around 500 euros for this coin in the next auction. It is important to note that this is just an estimate and the final price may vary depending on demand and other factors in the auction.