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 of high quality. This generally affects the price, as coins in better condition tend to fetch higher prices.

2. Auction History:
- The average hammer price for this coin in the past has been 166.58 euros.
- The coin has been auctioned 123 times, of which it has sold 109 times, indicating good demand.
- Previous hammer prices for coins with a similar condition (70) have varied, but recent auctions have seen hammer prices of 50 euros.

3. Starting Price and Estimated Prices:
- The current starting price is 40 euros, which is relatively low compared to the average hammer price.
- The average starting price in the past has been 65.53 euros, suggesting that the current starting price could be attractive to buyers.

4. Recent Trends:
- In the most recent auctions, hammer prices for coins with similar condition have ranged from 30 to 55 euros.

Based on these factors, an estimated maximum purchase price for this coin could be between 80 and 120 euros. This is because, although the condition is not the best, the demand and price history suggest that buyers may be willing to pay a bit more than the previous average hammer price, especially if the coin is considered a good buying opportunity in the current context.