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+), indicating that it is in relatively good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Current Starting Price and Previous Prices: The current starting price is 60 euros, and the average hammer price in previous auctions is approximately 77.87 euros. This suggests that the hammer price tends to be above the starting price.

3. Sales History: The coin has been sold in 26 out of the 43 previous auctions, indicating reasonable demand. Additionally, the highest recorded hammer price in the past was 150 euros for a coin with a condition rating of 90.

4. Recent Trends: In the most recent auctions, hammer prices have ranged from 55 to 85 euros, suggesting that interest in this coin remains steady.

Based on these factors, an estimated maximum purchase price could be in the range of 85 to 100 euros. This is because, given the condition and price history, it is reasonable to expect that a collector would be willing to pay a bit more than the previous average hammer price, especially if the coin is in good condition.

Therefore, an estimated maximum purchase price could be 95 euros.