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

1. Current Condition: The coin has a condition of 70 (MS-). This is an important factor, as coins in better condition tend to reach higher prices.

2. Historical Prices: Looking at previous auction prices for coins with similar conditions:
- In 2020, a coin with a condition of 70 was auctioned for 43 euros.
- In 2018, another coin with the same condition sold for 50 euros.
- In 2022, a coin with a condition of 70 was auctioned for 100 euros.

3. Average Auction Price: The average auction price for this coin is 175.17 euros, indicating that there is a higher selling potential in the market.

4. Starting Price and Average Starting Price: The current starting price is 30 euros, and the average starting price is 87.83 euros. This suggests that the market is willing to pay more than the starting price.

5. Market Trends: Given that the coin has been auctioned 47 times and has had a high sales percentage (44 out of 47), this indicates a consistent demand.

Based on these factors, an estimated maximum purchase price could be between 100 and 150 euros, considering that condition is a key factor and there are precedents for sales in that range. However, given the average auction price and price trends, a reasonable maximum purchase price could be 150 euros.