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

1. Starting Price: 1500 euros.
2. Condition: The coin has a condition rating of 80 (MBC+), which is good but not the best. This may influence the price.
3. Auction History:
- The average hammer price in previous auctions is 1127.93 euros.
- The coin has had a hammer price of 1000 euros in previous auctions with the same condition (80).
- In recent auctions, hammer prices have varied, reaching up to 1400 euros in an auction with a condition of 70.

4. Price Trends:
- In previous auctions, hammer prices have shown a gradual increase, especially for coins in better condition.
- The last auction with a condition of 85 reached a hammer price of 2200 euros, indicating that there is an active market willing to pay more for coins in better condition.

5. Proximity of the Auction: There is an auction scheduled in the coming days, which may generate additional interest and potentially increase the hammer price.

Based on these factors, an estimated maximum purchase price could be between 1300 and 1600 euros. This is because the starting price is 1500 euros, and considering the hammer price history, a buyer might be willing to pay a little more, especially if there is interest in the coin. However, it is important not to exceed the starting price to avoid overpaying at the auction.

Therefore, a reasonable maximum purchase price could be 1600 euros.