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 indicates that it is in an acceptable state, but not of high quality. Coins with a higher condition tend to reach higher prices at auctions.

2. Auction History:
- The average hammer price for similar coins in the past is 571.38 euros.
- The condition of the coins that have been sold in the past varies, but there are examples of coins with conditions of 75 and 90 that have reached significantly higher prices (for example, 3639.55 euros for a coin with a condition of 75).

3. Starting and Hammer Price:
- The current starting price is 50 euros, which is relatively low compared to the average hammer price.
- The average starting price of 364.95 euros also suggests that there is potential for an increase in the hammer price.

4. Recent Trends:
- In the most recent auctions, the hammer prices for coins with similar conditions have ranged between 60 and 230 euros, indicating that there is moderate interest in this price range.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 200 to 300 euros. This is based on the auction price history for coins of similar condition and the potential for an increase in the hammer price depending on demand at the auction.

Therefore, a reasonable maximum purchase price could be 250 euros.