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

1. Current Condition: The coin has a condition rating of 80 (MBC+), indicating that it is in fairly good shape, but not the best possible condition. This can influence the price, as coins in better condition tend to fetch higher prices.

2. Starting Price and Average Hammer Price: The starting price is 1500 euros, and the average hammer price in previous auctions is 1517.14 euros. This suggests that the hammer price is usually close to the starting price.

3. Auction History: In the past, the coin has had several hammer prices. For example, in the 2022 auction, it sold for 3600 euros, but that was for a coin with a condition rating of 95, indicating that the condition has a significant impact on the price. In other auctions, hammer prices have varied, but they have generally been in the range of 800 to 2000 euros.

4. Price Trends: The overall trend seems to be that hammer prices can be quite variable, but generally, for coins of similar condition, hammer prices have been in the range of 1300 to 2000 euros.

Given all this, an estimated maximum purchase price could be set in a range that considers the current condition and the price history. A reasonable maximum price could be:

Estimated maximum purchase price: 1800 euros.

This price takes into account the condition of the coin and the history of hammer prices, as well as the current starting price.