Based on the data provided, we can observe that the coin in question has had a starting price in the current auction of 45 euros and is in a conservation grade of 70 (MBC-). Additionally, it has been auctioned a total of 17 times in the past, with an average starting price of 71.88 euros and an average closing price of 123.24 euros.

When analyzing the previous prices of this coin in past auctions, we can see that it has had a considerable variation in starting, estimated, and closing prices over the years. However, overall, the closing prices have been higher than the starting and estimated prices in most cases.

Given that the current conservation grade of the coin is 70 (MBC-) and considering the trend of previous closing prices, as well as the fact that it has sold in all past auctions, we could estimate a maximum purchase price around 130-140 euros for this coin in the current auction. This is considering that previous closing prices have been higher than the current starting price and that the coin has had consistent demand in previous auctions.

It is important to note that the final closing price may vary depending on factors such as demand in the current auction, competition from other bidders, and specific interest in this particular coin.