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

1. Condition: The coin has a condition rating of 95 (S/C-), indicating that it is in very good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Starting Price: The starting price is 3000 euros, which sets a baseline for the auction.

3. Auction History:
- The average hammer price in previous auctions is 509.36 euros, but this includes coins of varying conditions.
- In past auctions, coins with similar conditions (around 90-95) have sold for prices that varied significantly, with some hammer prices reaching up to 5400 euros (as seen in the 2014 auction).

4. Price Trends: Observing the hammer prices of coins with similar conditions, it appears there is a wide range, but coins in better condition tend to fetch higher prices.

5. Market Expectations: Given that the coin will be auctioned in the near future and considering the potential demand, it is reasonable to expect that the hammer price could exceed the starting price.

Based on these factors, an estimated maximum purchase price could be between 4000 and 6000 euros, considering that the condition is high and there are precedents for successful sales in that range. However, the final price will depend on the competition in the auction and the interest of collectors.