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

1. Current Condition: The coin has a condition of 70 (VF-), which indicates that it is in relatively good shape, but not among the best qualities.

2. Historical Prices: By looking at previous auction prices for coins with a similar condition (70), we can see that the hammer price has varied. For example, in past auctions, coins with a condition of 70 have reached hammer prices of up to 80 euros.

3. Average Hammer Price: The average hammer price for this coin is 165.94 euros, but this includes coins of different conditions. Given that the condition of the coin in question is 70, it is likely that its hammer price will be below this average.

4. Recent Trends: In the most recent auctions, hammer prices for coins with a condition of 70 have been in the range of 25 to 40 euros, suggesting that interest and demand may be fluctuating.

5. Starting Price: The starting price is 15 euros, indicating that the auctioneer expects moderate interest.

Taking all these factors into account, an estimated maximum purchase price for this coin could be in the range of 40 to 60 euros. This is based on the current condition, previous hammer prices, and market trends.