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 85 (ebc-). This indicates that it is in quite good shape, which can positively influence its value.

2. Auction History:
- The average hammer price for similar coins in the past has been 66.99 euros.
- In previous auctions, coins with a similar condition (85) have reached hammer prices that vary, but there are examples of sales in the range of 30 to 80 euros.

3. Starting Price and Average Starting Price:
- The current starting price is 30 euros, and the average starting price in the past has been 34.69 euros. This suggests that the starting price is reasonable and could attract bidders.

4. Recent Trends:
- In the most recent auctions, hammer prices have shown a trend of being higher, especially for coins in good condition.

5. Supply and Demand:
- There are 3 auctions scheduled in the coming days, which may increase competition and, therefore, the hammer price.

Taking all these factors into account, an estimated maximum purchase price for this coin could be in the range of 80 to 100 euros. This range considers the good condition of the coin, the auction price history, and the potential competition in the auction.