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

1. Starting price: 60 euros.
2. Average hammer price in the past: 65 euros.
3. Condition of the coin: 70 (MBC-), which indicates good condition, although not the best.
4. Auction history: It has been auctioned once in the past and sold on that occasion, suggesting there is interest in the coin.

Given that the average hammer price in the past was 65 euros and considering that the condition of this coin is good (70), it is reasonable to think that the hammer price could be in a similar range or slightly higher, especially if there is interest in the current auction.

Taking all these factors into account, an estimated maximum purchase price could be between 70 and 80 euros. This is based on the fact that the condition is good and that interest in the coin could lead to a hammer price higher than the previous average.

Therefore, an estimated maximum purchase price could be 75 euros.