To estimate a maximum purchase price for the coin in question, let's consider several factors:

1. Starting Price: 150 euros. This is the initial price of the auction.
2. Condition: The coin has a condition rating of 70 (VF-), indicating that it is in relatively good shape, but not of high quality like the one sold in the past with a condition rating of 95.
3. Auction History: The coin has been auctioned once before, with a starting price of 500 euros and a hammer price of 26,000 euros. This suggests that there is significant interest in this coin, although the condition in that auction was significantly better.
4. Average Starting and Hammer Price: The average starting price is 325 euros and the average hammer price is 26,000 euros. This indicates that, in general, coins of this reference have a high market value.

Given that the current condition is lower than that of the previous auction, the hammer price will not be as high. However, the interest in the coin and the average hammer price suggest that there could be good selling potential.

Taking all these factors into account, an estimated maximum purchase price could be in the range of 1,500 to 2,500 euros. This is based on the current condition and historical interest in the coin, as well as the average hammer price.