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-), indicating that it is in an acceptable state, but not of the highest quality. This may influence the price, as coins in better condition tend to fetch higher prices.

2. Auction History:
- It has been auctioned 6 times in the past, of which 5 have been sold. This indicates a consistent interest in the coin.
- The average hammer price in previous auctions is 143.75 euros, providing a good reference point.
- In past auctions, hammer prices have varied, with a maximum of 220 euros in 2021 and a minimum of 80 euros in 2011.

3. Current Starting Price: The starting price is 40 euros, which is significantly lower than the average hammer price. This may indicate a good buying opportunity.

4. Price Trends: The average starting price in previous auctions is 86.67 euros, suggesting that the current starting price is low compared to the historical average.

Based on these factors, an estimated maximum purchase price could be positioned between the average hammer price and the highest price reached in previous auctions. Given that the condition is 70, it is reasonable to adjust the price towards the lower end of that range.

Estimated Maximum Purchase Price: It may be reasonable to consider a maximum purchase price of around 150 euros, taking into account the price history and the current condition of the coin.