Based on the data provided, we can observe that the coin in question has had an average auction closing price of 83.11 euros in previous auctions. Additionally, the condition of this coin has been described as '30 (BC+).'

Considering that the coin's condition is relatively low (BC+), but taking into account its strong performance in previous auctions, we could estimate a maximum purchase price around 90-100 euros. This is because, despite not being in the best condition, the coin has proven to be attractive to collectors and has fetched prices above its face value in previous auctions.

It is important to note that the final price of the coin at auction will depend on various factors, such as demand at that specific time, competition from other bidders, and buyers' willingness to pay a premium for this particular coin.