Based on the provided data, we can observe that the coin in question has had a starting price in the current auction of 6 euros and is in a conservation state of 20 (BC-). Additionally, it has been auctioned in the past on several occasions, with varying starting and estimated prices.

The average starting price of the coin in previous auctions has been 34.29 euros, while the average final price has been 49.55 euros. The coin has been sold in 12 out of the 15 previous auctions.

Some previous prices of the coin have ranged between 8 and 60 euros, with estimates ranging from 9 to 200 euros. The conservation state of the coin has varied in previous auctions, with values ranging from 30 to 85.

Given that the coin is in a conservation state of 20 (BC-) and has had previous estimated prices ranging from 9 to 200 euros, we could estimate a maximum purchase price around 150 euros. However, please note that the final auction price may vary depending on the demand in the current auction.