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-). This is an important factor, as coins in better condition tend to reach higher prices.

2. Auction History:
- In the past, this coin has been auctioned 4 times, of which it has sold 2 times. This indicates that there is interest in the coin, but also that there is a 50% no-sale rate, which may influence the perception of its value.
- Previous hammer prices are relevant. For example, in 2014, the coin sold for 124.81 euros, which is a considerably high price compared to the current starting price of 50 euros.

3. Average Hammer Price: The average hammer price of 89.9 euros is a good indicator of the value that buyers are willing to pay.

4. Starting Price: The starting price is 50 euros, which is relatively low compared to previous hammer prices.

5. Market Trends: Since there are no auctions scheduled in the coming days, this may increase competition among bidders interested in this coin.

Taking all these factors into account, an estimated maximum purchase price could be in a range between the average hammer price and the highest previous hammer price.

Therefore, an estimated maximum purchase price could be around 100 euros. This is based on the coin's condition, the demonstrated interest in previous auctions, and the average hammer price.