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

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

2. Auction History: The coin has been auctioned 42 times, of which it has sold 36 times. This suggests there is consistent interest in the coin. The average hammer price is 85 euros, providing a good reference.

3. Previous Prices: Looking at previous hammer prices, several prices stand out:
- In 2022, it sold for 500 euros (although the starting price was 80 euros).
- In 2024, it sold for 350 euros with a starting price of 250 euros.
- Other hammer prices ranged from 20 to 121 euros.

4. Price Trends: Hammer prices have varied considerably, but there seems to be an increase in prices at recent auctions, especially for coins in better condition.

Given that the coin has a condition rating of 80 (EF+) and considering the average hammer price of 85 euros, as well as the higher prices reached in recent auctions, an estimated maximum purchase price could be in the range of 150 to 200 euros. This is based on the trend that coins in better condition tend to reach higher prices, especially if there is interest in the auction.

Therefore, an estimated maximum purchase price could be 200 euros.