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

1. Current asking price: 600 euros.
2. Coin condition: 80 (MS+), indicating good condition.
3. Auction history:
- The coin has been auctioned 7 times and has sold on all occasions.
- The average hammer price in previous auctions is 1085.86 euros.
- Previous hammer prices have varied, but generally, they have been in a range that suggests the coin has good market value.

4. Previous hammer prices:
- In 2020, with a condition of 80, it sold for 800 euros.
- In 2018, with a condition of 75, it also sold for 800 euros.
- In 2021, with a condition of 75, it sold for 900 euros.
- In 2024, with a condition of 75, it sold for 701 euros.

Given that the current condition of the coin is 80, which is higher than the conditions of 75 in previous auctions, we can infer that the hammer price could be higher than the 800 euros from previous auctions.

### Estimation of the maximum purchase price:
- Considering the average hammer price of 1085.86 euros and the history of hammer prices, a reasonable maximum purchase price could be in the range of 900 to 1100 euros, given that the condition is better than in previous auctions.

Therefore, an estimated maximum purchase price could be approximately 1100 euros.