Based on the provided data, we can observe that the coin in question had a starting price of 75 euros in the most recent auction, with a conservation grade of 70 (MBC-). Additionally, it has been auctioned in the past on several occasions, with starting prices ranging from 25 to 200 euros.

The average starting price of previous auctions has been 91.6 euros, while the average final price has been 121.1 euros. The coin has been sold in 20 out of the 24 auctions it has participated in the past.

Taking into consideration these data, as well as the coin's previous prices and its current conservation grade, we could estimate a maximum purchase price around 150-180 euros. Given that the coin has had higher starting prices in the past, and considering its conservation grade and the trend of final prices, an estimated maximum purchase price in that range could be a good reference for the upcoming auction.