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

1. Condition: The coin has a condition rating 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. Auction History:
- The average hammer price in previous auctions is 28.6 euros.
- The coin has been auctioned 16 times, of which it has sold 11 times, indicating good demand.
- In previous auctions, the hammer price has varied, but there are examples of sales that have reached up to 110 euros under similar conditions.

3. Starting Price: The current starting price is 30 euros, which is a good starting point.

4. Price Trends: Observing previous hammer prices, it seems there is a price range that varies depending on the condition and demand at the time of the auction.

Given that the condition of this coin is quite good and considering the price history, an estimated maximum purchase price could be in the range of 50 to 70 euros. This is based on the fact that, although the starting price is 30 euros, the condition and demand could lead to a higher hammer price.

Therefore, an estimated maximum purchase price could be 70 euros.