Based on the provided data, the coin in question has a conservation grade of 70 (MBC-), with a starting price at the last auction of 200 euros and an estimated price of 350 euros. Considering the relatively good conservation grade and the estimated price of 350 euros, we could consider a maximum purchase price around 300-350 euros. It is important to note that the final auction price may vary depending on demand and other factors, so it is advisable to monitor the auction to adjust the offer accordingly.