To estimate a maximum purchase price for the coin in question, we can analyze the provided data:

1. Starting price: 2500 euros.
2. Current condition: 80 (MBC+).
3. Auction history: The coin has been auctioned 7 times and has sold on all occasions. The average hammer price in the past has been 2901.67 euros.
4. Previous hammer prices:
- In 2020, it was hammered at 2400 euros with a condition of 80.
- In 2015, it was hammered at 1910 euros with a condition of 80.
- In 2015, it was hammered at 2800 euros (condition not specified).
- In 2014, it was hammered at 3300 euros (condition not specified).
- In 2022, it was not hammered (condition of 80).
- In 2023, it was hammered at 3400 euros with a condition of 85.

Based on this data, we can observe that:

- The current condition of the coin (80) has had hammer prices ranging from 1910 to 2400 euros in previous auctions.
- However, in recent auctions, coins with a slightly higher condition (85) have reached hammer prices of up to 3400 euros.

Given that the average hammer price is 2901.67 euros and considering that the condition of the coin is 80, an estimated maximum purchase price could be positioned in a range between the average hammer price and the highest hammer price observed for similar conditions.

Therefore, an estimated maximum purchase price could be approximately 3000 euros. This is based on the trend of previous hammer prices and the current condition of the coin.