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

1. Current Condition: The coin has a condition rating of 80 (MS+), indicating that it is in good condition. This generally increases its value compared to coins with lower conditions.

2. Auction History:
- The coin has been auctioned 6 times, of which it has sold 5 times. This suggests there is consistent interest in the coin.
- Previous hammer prices varied, but the highest was 65 euros in 2018, with a condition of 70.
- In more recent auctions, hammer prices have been lower, especially for coins in condition 30.

3. Starting Price and Average Price:
- The current starting price is 50 euros, which is higher than the average starting price of 33.13 euros. This may indicate that the seller has higher expectations due to the good condition of the coin.
- The average hammer price is 41 euros, which is also an indicator of what buyers are willing to pay.

4. Price Trends:
- The trend of hammer prices seems to be slightly increasing, especially for coins in better condition.

Given all this, and considering that the condition of this coin is superior to that of previous auctions that have reached higher prices, an estimated maximum purchase price could be in the range of 70 to 80 euros. This is based on the good condition and the demonstrated interest in previous auctions.

Therefore, an estimated maximum purchase price could be 75 euros.

To estimate a maximum purchase price for the coin in question, we can analyze the provided data, especially the previous auction prices and the current condition of the coin.

1. Current Condition: The coin has a condition of 75 (MBC), which is an average condition. This suggests that its value will not reach the higher prices seen in coins of better condition.

2. Previous Auction Prices:
- In previous auctions, coins with a condition of 75 have reached auction prices that vary considerably. For example:
- In 2011, a coin with a condition of 75 was auctioned for 420 euros.
- In 2013, another coin with a condition of 75 was auctioned for 250.03 euros.
- In 2014, a coin with a condition of 75 was auctioned for 821.62 euros.
- In 2015, a coin with a condition of 75 was auctioned for 400 euros.
- In 2022, a coin with a condition of 90 (better than 75) was auctioned for 270 euros.

3. Average Auction Price: The average auction price for similar coins is 212.49 euros, which can serve as a good indicator of the expected value.

4. Starting Price: The current starting price is 75 euros, indicating that the seller expects a lower price initially.

5. Auction Trends: Given that the coin has been auctioned 56 times in the past and has sold 44 times, there is good demand for this coin, which may increase its value.

### Estimation of Maximum Purchase Price:
Considering all these factors, a reasonable maximum purchase price could be in the range of 200 to 300 euros, considering that:
- The condition is 75, which limits the maximum price.
- Previous auction prices for coins with the same condition have reached up to 420 euros, but that is an exceptional case.
- The average auction price is 212.49 euros, suggesting that a purchase price around 250 euros would be competitive and reasonable.

Therefore, an estimated maximum purchase price could be approximately 250 euros.