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

1. Current Condition: The coin has a condition of 85 (ebc-), which indicates 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 similar conditions (especially those with a condition of 80 and 85), we can see that they have reached significant auction prices. For example:
- In 2017, a coin with unspecified condition was auctioned for 2300 euros.
- In 2021, a coin with a condition of 80 sold for 1600 euros.
- In 2023, a coin with a condition of 85 sold for 7000 euros.

3. Average Auction Price: The average auction price for this coin is 1407.41 euros, which provides a benchmark.

4. Starting Price: The starting price is 3000 euros, indicating that the seller expects a higher price, but it may also influence the perception of the coin's value.

5. Auction Trends: The coin has been auctioned 19 times, with a high sales percentage (18 out of 19). This suggests that there is consistent interest in this coin.

Based on these factors, an estimated maximum purchase price could range between 2000 and 7000 euros, depending on the competition in the auction and the interest from collectors. Given that the condition is good and there are precedents for high sales, a reasonable maximum price could be approximately 5000 euros. This allows for a margin for competition and interest in the coin.