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

1. Current Condition: The coin has a condition of 70 (VF-). This is an important factor, as coins in better condition tend to reach higher prices.

2. Auction History:
- The average hammer price in previous auctions is 202.85 euros, indicating that, in general, coins of this reference tend to sell for significantly higher prices than the starting price.
- The last auction with a notable hammer price was in 2015, where a coin with a condition of 90 sold for 508.48 euros. This suggests that coins in better condition can reach very high prices.

3. Starting Price and Average Starting Price:
- The current starting price is 40 euros, which is quite low compared to the average hammer price. This could indicate a good buying opportunity.

4. Sales Trends: Of the 12 times it has been auctioned, it has sold on 9 occasions, showing consistent interest in this coin.

5. Estimation Based on Condition: Given that the condition of this coin is 70, we can estimate that its hammer price could be in a lower range than coins in better condition (like the one with a condition of 90 that sold for over 500 euros). However, given the price history, a hammer price in the range of 200-300 euros could be reasonable.

Taking all these factors into account, an estimated maximum purchase price for this coin could be between 200 and 250 euros. This would provide a good buying opportunity, considering the price history and the current condition of the coin.