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-), indicating that it is in an acceptable state, but not of the highest quality.

2. Previous Auction Prices: By observing the auction prices of coins with a similar condition (70), we can see that they have varied, but generally sold in a range of 50 to 150 euros. For example:
- In 2020, a coin with a condition of 70 was auctioned for 60 euros.
- In 2019, it was auctioned for 51 euros.
- In 2018, it was auctioned for 50 euros.

3. Average Auction Price: The average auction price for this coin is 97.68 euros, suggesting that, in general, coins of this reference tend to sell for a price above 50 euros.

4. Starting Price: The current starting price is 40 euros, which is relatively low compared to previous auction prices.

5. Trends: Since the coin has been auctioned 34 times and has had a sell-through rate of 94% (32 out of 34), this indicates a consistent demand.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 90 to 110 euros, considering that the average auction price is 97.68 euros and that the condition is acceptable. Therefore, a reasonable maximum purchase price could be 100 euros.