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. Previous Prices: By looking at previous auction prices for coins with a similar condition (80), we can see that they have reached auction prices that vary, but are generally above the current starting price of 250 euros. For example:
- In the 2021 auction, a coin with a condition of 80 sold for 240 euros.
- In the 2020 auction, a coin with a condition of 80 sold for 210 euros.

3. Price Trends: The average auction price for this coin is 267.21 euros, suggesting that, in general, coins of this reference tend to sell for above their starting price.

4. Starting Price and Estimates: The starting price is 250 euros, and the average starting price in previous auctions is 156.72 euros. This indicates that the current starting price is relatively high, but also that there is interest in this coin.

5. Future Auctions: There are 2 auctions scheduled in the coming days, which could increase competition and, therefore, the final auction price.

Taking all these factors into account, an estimated maximum purchase price could be around 300-350 euros. This is based on the highest auction price observed in previous auctions and the good condition of the coin. However, the final price will depend on the competition in the auction and the interest from other bidders.