Based on the data provided, we can observe that the coin in question has had varying starting and final prices in previous auctions, ranging from 18 euros to 350 euros. The estimated price has also varied, with values ranging from 30 euros to 700 euros.

Considering that the current condition of the coin is 30 (BC+), and taking into account the previous prices of similar auctions as well as the average final price of 213.25 euros, we could estimate a maximum purchase price around 250 euros.

It is important to note that the final auction price will depend on various factors, such as demand at the time of the auction, the condition of the coin, and the willingness of participants to bid on it.