To estimate a maximum purchase price for the coin in question, we can analyze the provided data, especially the previous auction prices and the current condition of the coin.

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

2. Previous Auction Prices: By observing the auction prices of coins with similar conditions (around 70), we can see that:
- In previous auctions, coins with a condition of 70 have reached hammer prices of up to 70-190 euros.
- For example, in the auction on 2022-01-25, a coin with a condition of 90 was sold for 190 euros, and in the auction on 2022-04-26, a coin with a condition of 85 was sold for 170 euros.

3. Average Hammer Price: The average hammer price for this coin is 100.82 euros, which is also a good indicator of the expected value.

4. Auction Trends: The coin has been auctioned 36 times, of which 28 have sold. This suggests that there is a consistent interest in this coin, which may influence its price.

5. Starting Price: The starting price is 25 euros, which is relatively low compared to previous hammer prices.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 80 to 120 euros, considering that the condition is 70 and there is a history of hammer prices that supports this estimate.

Therefore, a reasonable maximum purchase price could be 100 euros.