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 quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Starting Price and Average Hammer Price: The current starting price is 60 euros, and the average hammer price in previous auctions is 76.51 euros. This suggests that, on average, similar coins have reached prices above the starting price.

3. Sales History: In the past, the coin has had hammer prices that varied significantly, with some reaching up to 420 euros in exceptional conditions (such as in 2018). However, most hammer prices fall within a lower range, around 50 to 150 euros.

4. Recent Trends: In the most recent auctions, hammer prices have been in the range of 80 to 130 euros for coins with similar conditions.

5. Estimation Based on Historical Data: Given that the coin has a condition rating of 80 and considering the average hammer price and recent hammer prices, an estimated maximum purchase price could be in the range of 100 to 120 euros.

### Final Estimation
Taking all these factors into account, an estimated maximum purchase price for the coin could be 120 euros. This price reflects both the good condition of the coin and the historical hammer price trends in previous auctions.