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 good condition. This generally translates to a higher value compared to coins with lower conditions.

2. Auction History:
- The average hammer price in previous auctions is 60.17 euros, suggesting that this is a reasonable range to expect in an auction.
- The coin has been auctioned 12 times, of which it has sold 6 times. This indicates a moderate interest in the coin.

3. Previous Starting and Hammer Prices:
- In previous auctions, starting prices have varied, but the highest hammer price was 95 euros in 2017, when the condition was also 80.
- The current starting price is 60 euros, which is consistent with the average hammer price.

4. Price Trends:
- Given that the average hammer price is similar to the current starting price, and considering that the condition is good, it is reasonable to expect that the hammer price could be in the upper range of previous prices.

Based on these factors, an estimated maximum purchase price could be around 80-90 euros. This is based on the good condition of the coin and the hammer price history in previous auctions. However, it is important to note that collector interest and other market factors may also influence the final price.