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. Previous Prices: By looking at previous auction prices, we can see that in past auctions, coins with similar conditions have reached varying hammer prices. For example:
- In 2022, a coin with a condition of 70 was sold for 310 euros.
- In 2021, a coin with a condition of 80 was sold for 270 euros.
- In 2023, a coin with a condition of 95 was sold for 420 euros.

3. Starting Price and Average Hammer Price: The current starting price is 380 euros, and the average hammer price in previous auctions is 346.35 euros. This suggests that the starting price is relatively high compared to the historical average.

4. Auction Trends: The coin has been auctioned 27 times, with a 77.78% sell-through rate (21 out of 27). This indicates a consistent interest in the coin, which may influence its price.

5. Comparison with Estimated Prices: The estimated price for this auction is 500 euros, suggesting that there are expectations for the coin to reach a higher price.

Taking all these factors into account, an estimated maximum purchase price could be around 400-450 euros. This is based on the current condition, previous hammer prices, and interest in the coin. However, since the starting price is 380 euros, buyers may be willing to pay a little more, but not much beyond 450 euros, considering the condition and market context.