Based on the data provided, we can observe that the coin in question has had an average auction closing price of 59.2 euros in previous auctions. Additionally, its current condition is 90 (EBC).

Considering that the starting price for the next auction is 50 euros and that the coin has been sold in the past for prices ranging from 15 euros to 190 euros, with a maximum estimated price of 150 euros, we can estimate a maximum purchase price for this coin in the next auction.

Given that the coin has been sold in the past for prices higher than the current starting price and taking into account its condition and the previous average closing price, we could estimate a maximum purchase price around 160 euros.

It is important to note that the final auction price will depend on several factors, such as the demand at that specific moment, the competition from other bidders, and the buyers' perception of the coin's value at that time.