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

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

2. Historical Prices: By looking at previous auction prices for coins with a similar condition (80), we can see that the auction price has varied but has reached significant figures. For example:
- In 2021, a coin with a condition of 80 was auctioned for 240 euros.
- In 2020, it was auctioned for 210 euros.
- In 2016, it was also auctioned for 145 euros.

3. Average Auction Price: The average auction price for this coin is 267.21 euros, suggesting that, in general, buyers are willing to pay close to this figure.

4. Starting Price and Estimates: The starting price is 250 euros, and the average starting price is 156.72 euros. This indicates that the current starting price is relatively high, but not unusual for a coin in good condition.

5. Recent Trends: In the most recent auctions, the hammer prices have been quite high, suggesting an upward trend in interest for this coin.

Based on these factors, an estimated maximum purchase price could be around 300 euros. This is based on the condition of the coin, previous auction prices, and the current trend in the market. However, it is important to note that the final price may vary depending on competition in the auction and the interest of other buyers.