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

1. Starting price: 30 euros.
2. Average starting price: 35 euros.
3. Average hammer price: 45 euros.
4. Coin condition: 70 (MBC-), indicating good condition.
5. Auction history: The coin has been auctioned 2 times in the past, and on both occasions, it has sold. The most recent hammer price was 45 euros.

Given that the condition is good (70), and considering that the average hammer price has been 45 euros, we can estimate that the maximum purchase price could be in a range above the average hammer price, but not too high to avoid overpaying.

Taking all these factors into account, an estimated maximum purchase price could be approximately 50 euros. This is based on the fact that the highest hammer price in the past was 45 euros, and a slight increase could be reasonable given the interest in the coin and its good condition.