To estimate a maximum purchase price for the coin in question, we can analyze the provided data, including auction history and previous hammer prices.

1. Current Condition: The coin has a condition of 70 (VF-). This indicates that it is in an acceptable state, but not in the best condition.

2. Price History:
- The average hammer price for similar coins in the past is 426.95 euros.
- Previous hammer prices for coins with similar conditions (70) have varied, but there are examples of auctions that have reached up to 480 euros (such as in the auction on November 10, 2020).

3. Price Trends:
- The general trend shows that coins with a condition of 70 have had hammer prices ranging from 180 to 480 euros in the past.
- The most recent auction with a similar condition (70) had a hammer price of 240 euros.

4. Starting Price: The starting price is 220 euros, which suggests that the seller has reasonable price expectations.

5. Estimation: Given that the average hammer price is 426.95 euros and considering that the coin's condition is 70, a reasonable maximum purchase price could be in the range of 400 to 480 euros, depending on the competition in the auction and the interest of collectors.

Conclusion: An estimated maximum purchase price for this coin could be approximately 450 euros. This is based on the price history, current condition, and market context.