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 among the best qualities. This may influence the price, as coins in better condition tend to reach higher prices.

2. Auction History:
- In the past, the coin has been auctioned 7 times, of which it has sold 6 times. This indicates good demand.
- The average hammer price in previous auctions is 320 euros, suggesting that buyers are willing to pay close to this price.
- The last auction with a similar condition (70) had a hammer price of 320 euros.

3. Starting Price and Estimates:
- The current starting price is 300 euros, which is reasonable compared to the average hammer price.
- The average starting price in previous auctions is 287.14 euros, indicating that the current starting price is aligned with the history.

4. Price Trends:
- In the 2022 auction with a condition of 80, the hammer price was 400 euros, showing that better condition can significantly increase the price.

Based on these factors, an estimated maximum purchase price could be slightly above the previous average hammer price, considering that the condition is a limiting factor.

Estimated Maximum Purchase Price: 350 euros.

This price reflects a balance between the current condition and the price history, allowing for a margin for competition in the auction.