Based on the provided data, we can observe that the coin in question has had a starting price in previous auctions ranging between 30 and 60 euros, with estimated prices between 50 and 90 euros. The average selling price has been 60 euros.

Considering that the current condition of the coin is 30 (BC+), and that in the past it has reached estimated prices of up to 90 euros, we could estimate a maximum purchase price around 80 euros. However, keep in mind that the final price will depend on the demand at the auction and other factors that may influence the decision of potential buyers.