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 rating of 70 (VF-), indicating that it is in relatively good shape, although not the best possible condition.

2. Auction History:
- The average hammer price in previous auctions is 68.9 euros.
- The coin has been auctioned 11 times, of which it has sold 10 times, indicating good demand.
- In previous auctions, hammer prices have varied, with a maximum of 120 euros in 2017.

3. Starting Price and Estimates:
- The current starting price is 30 euros, which is relatively low compared to the average hammer price.
- The average starting price in previous auctions is 47.5 euros, suggesting that the current starting price could be attractive to buyers.

4. Recent Trends: In the most recent auction (2022), the coin sold for 40 euros, indicating that interest in the coin remains.

Based on these factors, an estimated maximum purchase price could be in a range between the average hammer price (68.9 euros) and the highest recorded price (120 euros). However, given that the current condition is 70, it is reasonable to adjust the estimate towards the lower end of this range.

Therefore, an estimated maximum purchase price could be approximately 80-90 euros. This reflects a balance between the condition, price history, and current demand.