Based on the provided data, we can observe that the coin in question has had an average starting price of 51.25 euros in previous auctions, with an average closing price of 93.67 euros. The coin's condition is described as "30 (BC+)".

Additionally, a total of 8 auctions have been conducted in the past, with the coin being sold in 6 instances and not sold in 2 instances. Previous auction prices for the coin have varied, with estimated starting and closing values, along with associated condition grades.

Considering these data points, and noting that the coin is in a "30 (BC+)" condition and has reached closing prices of up to 175 euros in previous auctions, we could estimate a maximum purchase price of around 160-180 euros for this coin in the upcoming auction. It is important to consider that the final price may vary depending on factors such as demand at the time of the auction and the interest of potential buyers.