To estimate a maximum purchase price for the coin in question, we can consider several factors based on the provided data:

1. Current Condition: The coin has a condition of 70 (VF-), indicating that it is in relatively good shape. This suggests that its value could be in the upper range of previous auctions.

2. Previous Auction Prices:
- The average hammer price for this coin has been 168.04 euros.
- In previous auctions, hammer prices have varied, but there are examples of sales reaching up to 650 euros (in a 2023 auction with a condition of 75).

3. Starting Price and Average Starting Price:
- The current starting price is 80 euros, which is below the average starting price of 92.17 euros. This could indicate that there is a buying opportunity at a lower price than average.

4. Recent Trends: In the most recent auctions, there has been an increase in hammer prices, especially for coins in good condition. This suggests that demand may be rising.

5. Comparison with Previous Prices:
- In previous auctions with a condition of 70, hammer prices have ranged between 60 and 170 euros, providing a reference range.

Based on these factors, an estimated maximum purchase price could be set in a range between 150 and 200 euros, considering that the condition is good and there is an upward trend in hammer prices. Therefore, a reasonable maximum purchase price could be 200 euros.