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-). This is an important factor, as coins in better condition tend to reach higher prices.

2. Auction History:
- The coin has been auctioned 8 times, of which it has sold 7. This indicates a consistent interest in the coin.
- The average hammer price in previous auctions is 867.14 euros, suggesting that, in general, buyers are willing to pay close to this price.

3. Previous Auction Prices:
- In 2019, a coin with a similar condition (70) sold for 400 euros.
- In 2014, a coin with a condition of 80 sold for 750 euros.
- In 2018, a coin with a condition of 95 sold for 1800 euros, indicating that condition has a significant impact on price.

4. Current Starting Price and Average Starting Price:
- The current starting price is 350 euros, which is below the average starting price of 475 euros. This could indicate a buying opportunity.

5. Price Trends:
- Hammer prices have varied, but the highest recorded price for a coin of similar condition was 400 euros in 2019.

Based on these factors, an estimated maximum purchase price could be in the range of 600 to 800 euros, considering that condition is a limiting factor and that interest in the coin appears to be high. A price of 700 euros could be a reasonable target, as it is in the middle of this range and aligns with the auction price history.