Based on the data provided, we can observe that the coin in question has had an average starting price in previous auctions of 23.8 euros and an average closing price of 35.6 euros. Additionally, it has been auctioned off five times before, always selling.

The current condition of the coin is rated at 30 (BC+), indicating that it is in an acceptable but not excellent condition.

Looking at the previous prices of this coin in past auctions, we see that it has had a wide price range, starting from 15 euros up to 45 euros for the starting price, with estimates ranging from 40 euros to 75 euros. The closing price has fluctuated between 18 euros and 45 euros.

Given that the coin has sold in all previous auctions and its current condition is rated at 30 (BC+), we could estimate a maximum purchase price around the average closing price, approximately 35.6 euros. However, keep in mind that the final price in an auction can vary depending on demand and other factors, so it is important to be prepared to adjust your offer accordingly.