Based on the data provided, we can observe that the coin in question has had an average starting price in previous auctions of 40.3 euros, with an average closing price of 68.8 euros. The current condition of the coin is 70 (VF+).

When analyzing the previous prices of this coin in past auctions, we can see that it has had a fairly wide price range, with starting prices ranging from 25 euros to 90 euros, estimated values ranging from 40 euros to 150 euros, and closing prices ranging from 31 euros to 190 euros. The condition of the coins auctioned in the past has mostly been between 70 and 95.

Given that the coin will be auctioned with a starting price of 18 euros and considering its price history, condition, and demand in previous auctions, we could estimate a maximum purchase price of around 90 euros. This is considering that the coin is in a condition of 70 (VF+) and has had previous closing prices that have exceeded 90 euros.

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