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

1. Condition: The coin has a condition of 70 (MBC-), which indicates that it is in quite good shape. This generally suggests that the hammer price could be higher than that of coins in worse conditions.

2. Auction history:
- In 2015, the coin was auctioned with a starting price of 60 euros and sold for 80 euros, indicating significant interest in that auction.
- In 2022, the starting price was 30 euros and it sold for 30 euros, suggesting that interest was lower on that occasion.
- In 2024, the starting price was 12 euros and it sold for 12 euros, indicating that demand was very low.

3. Average prices: The average starting price is 33 euros and the average hammer price is 40.67 euros. This can serve as a reference for the estimated price.

4. Current starting price: The starting price is 30 euros, which is relatively low compared to the average hammer price.

Given that the coin has an auction history and considering its condition, an estimated maximum purchase price could be positioned between the average hammer price and the highest recorded hammer price.

Taking all this into account, an estimated maximum purchase price could be approximately 50-60 euros. This is based on the interest shown in previous auctions and the current condition of the coin.