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

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

2. Starting Price and Average Hammer Price: The current starting price is 120 euros, and the average hammer price in previous auctions is 169.78 euros. This suggests that, in general, coins of this reference tend to sell for above their starting price.

3. Sales History: The coin has been auctioned 47 times, of which 44 have been sold. This indicates good demand and a history of successful sales.

4. Previous Prices: Looking at previous hammer prices for coins with similar conditions (80-85), we can see that they have reached hammer prices of up to 220 euros in the past.

5. Recent Trends: In the most recent auctions, the hammer prices have shown a range that may indicate an increase in interest or value for the coin.

Based on these factors, an estimated maximum purchase price could be set in a range between 200 and 250 euros, considering that the average hammer price is 169.78 euros and that there are precedents for higher hammer prices for similar conditions.

Therefore, a reasonable maximum purchase price could be 250 euros.