Based on the information provided, we know that the coin will be auctioned for the first time and is in a conservation grade of 75 (MBC). Since there are no previous auction data for this coin, we can consider the starting price as an initial reference.
Given that the conservation grade is 75 (MBC), we can assume that the coin is not in perfect condition, but also not in poor condition. Considering that the starting price is 3000 euros, and considering that it is the first time being auctioned, we could estimate a maximum purchase price around 20% above the starting price.
Therefore, an estimated maximum purchase price for this coin in a conservation grade of 75 (MBC) could be around 3600 euros. It is important to note that this is just an estimate and the final price will depend on the demand at the auction and other factors that may influence the decision of potential buyers.