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

1. Condition: The coin to be auctioned has a condition of 80 (MBC+). This is an important factor, as coins in better condition tend to reach higher prices.

2. Previous Prices: By observing the hammer prices of coins with similar conditions (80 and 85), we can see that:
- In several auctions, coins with a condition of 80 have reached hammer prices between 350 and 400 euros.
- A coin with a condition of 85 sold for 410 euros, suggesting that a condition of 80 might be in a lower price range.

3. Average Hammer Price: The average hammer price for similar coins is 410 euros, indicating that this could be a good reference point.

4. Starting Price: The starting price is 200 euros, which may attract more bidders, but the final hammer price will depend on demand.

5. Auction Trends: Given that there have been 10 previous auctions and 7 of them resulted in sales, this suggests a consistent interest in this coin.

Based on these factors, an estimated maximum purchase price for the coin in question could be in the range of 400 to 500 euros, considering that the condition is good and that interest in the coin appears to be solid. A hammer price of around 450 euros could be a reasonable target, given the sales history and current condition.