To estimate a maximum purchase price for the coin in question, we can analyze the provided data, especially the previous auction prices and the current condition of the coin.

1. Current Condition: The coin has a condition of 80 (VF+). This is an important factor, as coins in better condition tend to reach higher prices.

2. Previous Auction Prices: Looking at the auction prices of coins with similar conditions:
- In 2016, a coin with a condition of 85 was auctioned for 950 euros.
- In 2024, a coin with a condition of 85 was auctioned for 2000 euros.
- In 2024, a coin with a condition of 80 was auctioned for 1000 euros.

3. Price Trends: The average auction price for this coin is 669.62 euros, indicating that, in general, coins of this reference tend to sell for above their starting price.

4. Current Starting Price: The starting price is 300 euros, which is relatively low compared to previous auction prices.

5. Estimation: Given that the condition of the coin is 80 and considering the previous auction prices, a reasonable maximum purchase price could be in the range of 800 to 1200 euros, depending on the demand at the auction and the interest from collectors.

Therefore, an estimated maximum purchase price for this coin could be approximately 1000 euros.