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

1. Coin Condition: The coin has a condition rating of 80 (MBC+), indicating that it is in relatively good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Current Listing Price and Previous Prices: The current listing price is 300 euros, and the average hammer price in previous auctions is 328.83 euros. This suggests that the hammer price tends to be close to the listing price, which is a good indicator.

3. Auction History: The coin has been auctioned 63 times, of which it has sold 49 times. This indicates good demand and consistent interest in the coin.

4. Previous Hammer Prices: In past auctions, hammer prices for coins with a similar condition (80) have varied, but there are examples of hammer prices reaching up to 650 euros (as seen in the March 2023 auction).

5. Price Trends: The average hammer price of 328.83 euros and the fact that there have been higher hammer prices in the past suggest that there is potential for the hammer price to exceed the current listing price.

Considering all these factors, an estimated maximum purchase price could be in the range of 400 to 600 euros, given that the condition is good and there is a history of hammer prices supporting this estimate.

Therefore, a reasonable maximum purchase price could be approximately 500 euros.

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

1. Coin Condition: The coin has a condition of 75 (MBC), indicating that it is in relatively good shape, but not among the best qualities.

2. Previous Prices: By observing the auction prices of coins with similar conditions (around 70-80), we can see that the auction prices have varied. For example:
- A coin with a condition of 70 was auctioned for 30 euros.
- Another with a condition of 80 was auctioned for 47 euros.
- A coin with a condition of 85 was auctioned for 55 euros.

3. Average Auction Price: The average auction price for this coin is 195.83 euros, but this may be influenced by coins in better condition or exceptional auctions.

4. Average Starting Price: The average starting price is 105.28 euros, which can give an idea of what buyers are initially willing to pay.

5. Auction Trends: The coin has been auctioned 80 times, of which it has sold 67 times, indicating good demand.

6. Starting and Estimated Prices: The current starting price is 25 euros, and the estimated price is 60 euros. This suggests there is potential for an increase in the auction price.

Taking all these factors into account, an estimated maximum purchase price for this coin could be between 50 and 80 euros, considering that the condition is good but not excellent, and that previous auction prices for similar conditions have not exceeded 55 euros in most cases.

Therefore, a reasonable maximum purchase price could be 70 euros.