Based on the provided data, we can observe that the coin in question has had an average starting price of 35 euros in previous auctions, with a median closing price of 71 euros. The coin's condition has been described as 70 (VF+), indicating a fairly acceptable preservation.

Additionally, previous prices of this coin have been recorded in past auctions, with estimates ranging from 25 to 90 euros. Considering that the coin has sold in most previous auctions, we can infer that there is interest from collectors in this piece.

Given that the starting price this time is 30 euros and considering the upward trend in closing prices, as well as the relatively good condition of the coin, we could estimate a maximum purchase price around 80-90 euros. This takes into account that the estimated price in previous auctions has reached up to 90 euros and that the coin has sold in most instances.

It is important to note that the final auction price will depend on the demand at that specific moment, so it is advisable to monitor its evolution to adjust the offer accordingly.