Based on the information provided, we know that the coin will be auctioned for the first time and is in a conservation grade of 70 (MBC-). Since there are no previous auction data for this coin, we can consider the starting price as a reference.

Given that the conservation grade is 70 (MBC-), we can assume that the coin is not in perfect condition, but also not in poor condition. Considering that the starting price is 25 euros and the conservation is acceptable, we could estimate a maximum purchase price around 30-35 euros.

It is important to note that the final auction price will depend on the demand from buyers present at the auction, so this range is just an estimation based on the information provided.