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

1. Coin Condition: The coin has a condition rating of 70 (MBC-), which indicates 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 similar coins in the past is 158.66 euros.
- The coin has been auctioned 117 times, of which it has sold 105 times, indicating good demand.
- Previous hammer prices for coins with a similar condition (70) have varied, with some selling for 50 euros and others for 31 euros.

3. Starting Price and Estimated Prices:
- The current starting price is 25 euros, which is relatively low compared to the average hammer price.
- The estimated price for this auction is 40 euros, suggesting that the coin is expected to reach a higher price than the starting bid.

4. Recent Trends: In recent auctions, coins with a similar condition have reached hammer prices ranging from 30 to 80 euros.

Based on these factors, an estimated maximum purchase price for this coin could be between 60 and 80 euros, considering that the average hammer price is 158.66 euros, but adjusted for the condition and the hammer price history for similar coins.

Therefore, a reasonable maximum purchase price could be 70 euros.