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

1. Current Condition: The coin has a condition rating of 85 (ebc-), indicating that it is in fairly good shape, but not the best possible condition. This may 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 1506.88 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 2018 it was sold for 1100 euros with a condition rating of 95, and in 2021 it was sold for 1300 euros with a condition rating of 80. This indicates that the price can vary significantly depending on the condition and demand at the time of the auction.

4. Price Trends: Looking at previous hammer prices, the highest recorded price was 1755 euros in 2024, suggesting that there is potential for the price of this coin to increase based on demand.

Given all this, an estimated maximum purchase price could be around 1600-1700 euros. This range takes into account the current condition, price history, and the trend of increasing hammer prices. However, it is important to remember that the final price will depend on the competition in the auction and the specific demand at that time.