Based on the provided data, we can observe that the coin has had an average auction closing price of 81.25 euros in previous auctions. Additionally, it has been auctioned four times in the past, always selling.

The current condition of the coin is estimated to be 30 (BC+), indicating that it is not in the best condition, but it is not among the worst either.

Looking at the previous prices of the coin in past auctions, we see that it has had a wide price range, from 60 euros to 125 euros, with varying price estimates.

Given that the coin has sold in all previous auctions and the average closing price has been 81.25 euros, we could estimate a maximum purchase price around that value or slightly higher, considering the current condition of the coin. Therefore, an estimated maximum purchase price for this coin could be around 85-90 euros.