To estimate a maximum purchase price for the coin in question, we will consider several factors:

1. Coin Condition: The coin has a condition rating of 70 (MS-), indicating that it is in acceptable condition, but not among the highest quality.

2. Auction History:
- The average hammer price for similar coins in condition 70 has been approximately 60-90 euros in previous auctions.
- In the most recent auctions, hammer prices for coins with similar condition have ranged from 60 to 170 euros, depending on demand and other factors.

3. Starting Price and Average Hammer Price:
- The current starting price is 40 euros, and the average hammer price in the past has been 88.42 euros.

4. Auction Trends:
- The coin has been auctioned 102 times, with a high sales percentage (88 out of 102), indicating good demand.

Based on these factors, an estimated maximum purchase price could be in the range of 90 to 120 euros, considering that the average hammer price has been 88.42 euros and that the condition is 70. This also takes into account the possibility that demand may vary in the current auction.

Therefore, an estimated maximum purchase price could be 100 euros.