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

1. Current Condition: The coin has a condition of 80 (MS+), which indicates that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Historical Prices: By looking at previous auction prices for coins with similar conditions, we can see that:
- Coins with a condition of 75 have reached auction prices of up to 115 euros.
- Coins with a condition of 85 have reached auction prices of up to 135 euros.
- Coins with a condition of 90 have reached auction prices of up to 380 euros.

3. Average Auction Price: The average auction price for this coin is 167.38 euros, which is also a good indicator of the expected value.

4. Starting Price and Previous Sales: The current starting price is 60 euros, and there have been 50 previous sales, suggesting that there is interest in the coin.

5. Recent Trends: In the most recent auctions, the hammer prices have varied, but there are examples of similar coins that have reached hammer prices of 140 euros or more.

Based on these factors, an estimated maximum purchase price for this coin could be between 200 and 250 euros, considering its good condition and the hammer prices of similar coins in the past. This would allow for competitive bidding in the auction without exceeding a reasonable limit based on the sales history.