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 an acceptable state, but not among the best qualities.

2. Auction History:
- The average hammer price for coins with a similar condition (70) has been approximately 35.4 euros.
- In previous auctions, hammer prices for coins with a condition of 70 have varied, but the range has been between 15 and 40 euros, with some exceptional cases reaching up to 440 euros, although this is uncommon.

3. Starting Price: The current starting price is 35 euros, which is a good indicator of what is expected to be obtained in the auction.

4. Recent Trends: In the most recent auctions, hammer prices for coins with a condition of 70 have been around 30 to 70 euros, suggesting that there is moderate interest in this type of coin.

5. Maximum Price Estimate: Given that the average hammer price is 35.4 euros and considering that the condition is 70, a reasonable maximum purchase price could be in the range of 50 to 70 euros, depending on the demand in the auction.

Conclusion: Based on all these factors, an estimated maximum purchase price for this coin could be 70 euros. This would allow for effective competition in the auction without exceeding the historical hammer value for coins in similar conditions.