Based on the provided data, we can observe that the coin in question had a starting price of 90 euros in this auction and is in a conservation grade of 70 (MBC-). Additionally, it has been auctioned in the past 20 times, sold in 17 instances, and remained unsold in 3 instances.

The average starting price in previous auctions has been 154.25 euros, while the average final price has been 205.71 euros.

Some previous prices for this coin are as follows:

- In the auction on December 15, 2020, the coin had a starting price of 150 euros, an estimated price of 200 euros, and a final price of 220 euros, with a conservation grade of 80.
- In the auction on January 24, 2019, the coin had a starting price of 250 euros, an estimated price of 400 euros, and a final price of 380 euros, with a conservation grade of 95.
- In the auction on May 24, 2017, the coin had a starting price of 250 euros, an estimated price of 400 euros, and a final price of 420 euros.

Given that the coin is in a conservation grade of 70 (MBC-) and considering the previous prices, the average final price, and the fact that it has sold in most previous auctions, we could estimate a maximum purchase price around 220-250 euros. It is important to note that the final price may vary depending on demand at the auction and other external factors.