Based on the data provided, we can observe that the coin in question has had a starting price in the current auction of 250 euros, with a conservation grade of 70 (MBC-). Additionally, it has been auctioned 13 times before, always selling, with an average closing price of 281.15 euros.

When analyzing the previous prices of the coin in past auctions, we can see that it has had a varied price range, with estimates ranging from 175 euros to 550 euros. The conservation grade of the coin has been consistently 70 (MBC-) in previous auctions.

Given that the coin has sold in all previous auctions and the average closing price is 281.15 euros, we could estimate a maximum purchase price around that value or slightly higher, considering the demand and conservation of the coin.

Therefore, my estimate for the maximum purchase price for this coin in the current auction would be around 300-320 euros, taking into account its price history and conservation.