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

1. Starting price: 125 euros.
2. Average hammer price: 220 euros. This is an important piece of information, as it indicates the average price at which it has sold in the past.
3. Condition: The coin has a condition rating of 75 (VF), which suggests that it is in fairly good shape, but not the best possible condition.

Since the coin has been auctioned once and sold on that occasion, this indicates that there is interest in the coin. Additionally, the fact that there have been no failed sale attempts suggests that the starting price is attractive.

Taking into account the average hammer price of 220 euros and the condition of the coin, an estimated maximum purchase price could be set between the average hammer price and a little more, considering that the condition is good but not excellent.

Therefore, an estimated maximum purchase price could be around 250 euros. This allows for some competition in the auction and reflects the interest that there might be in the coin.