Based on the data provided, we can observe that the coin in question has had an average starting price of 48.07 euros in previous auctions, with an average closing price of 88.29 euros. The current condition of the coin is graded at 30 (BC+).

Additionally, closing prices in previous auctions have ranged from 20 euros to 240 euros, with conservation values fluctuating between 30 and 90.

Given that the coin has been auctioned 15 times in the past and sold on 14 occasions, we can infer that there is market interest in this coin.

Taking into account these data, as well as the upward trend in closing prices, an estimated maximum purchase price for this coin in the next auction could be around 200 euros. It is important to note that this is just an estimate and the final price will depend on various factors, such as demand at the time of the auction and the specific condition of the coin in question.