Based on the provided data, we can observe that the coin in question had a starting price of 30 euros in this auction, with a conservation grade of 30 (BC+). Additionally, it has been auctioned four times in the past, with an average starting price of 88.75 euros and an average closing price of 121.25 euros.

Regarding the previous prices of this coin, we can see that in the last recorded auction in 2017, the coin had a starting price of 125 euros, an estimated price of 225 euros, and closed at 130 euros. In 2016, it had a starting price of 90 euros, an estimated price of 150 euros, and closed at 110 euros. In 2014, the starting price was 110 euros, the estimated price was 200 euros, and it closed at 160 euros.

Given that the coin is in a conservation grade of 30 (BC+), and considering the previous auction prices, as well as the starting and closing prices of this current auction, we could estimate a maximum purchase price around 140-150 euros. It is important to note that the final price may vary depending on the demand at the auction and other factors that may influence buyers' decisions.