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

1. Current Condition: The coin has a condition of 70 (VF-), indicating that it is in an acceptable state, but not of the highest quality. This may influence the price, as coins in better condition tend to fetch higher prices.

2. Auction History:
- In the past, this coin has been auctioned 4 times and has sold on all occasions.
- The highest hammer price was 200 euros for a coin with a condition of 80, indicating that there is a market for high prices, but also that condition significantly influences the price.
- The average hammer price for previous auctions is 77.25 euros, providing a good reference point.

3. Starting Price and Estimates:
- The current starting price is 25 euros, which is reasonable given the price history.
- The estimated hammer price for the current auction is 50 euros, suggesting that there may be moderate interest in the coin.

4. Comparison with Previous Prices:
- In the January 2023 auction, a coin with a condition of 80 sold for 200 euros, indicating that there is potential for high prices, but also that condition is a key factor.
- In the February 2023 auction, a coin with a condition of 85 sold for 70 euros, suggesting that the price range can vary significantly depending on the condition.

Taking all these factors into account, an estimated maximum purchase price for the coin with a condition of 70 could be in the range of 50 to 80 euros, considering that interest may be moderate and that the condition is not the best. A reasonable maximum price could be 70 euros.