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-), indicating that it is in quite good shape. This suggests that its value should be in the upper range of previous auctions.

2. Previous Auction Prices: By looking at the hammer prices of coins with similar conditions (85), we can see that they have reached hammer prices of up to 500 euros in the past. However, most hammer prices for condition 85 have been in the range of 140 to 265 euros.

3. Average Hammer Price: The average hammer price for this coin is 141.7 euros, which can also serve as an indicator of its value.

4. Starting Price and Average Starting Price: The current starting price is 70 euros, and the average starting price is 91.75 euros. This suggests that the starting price is relatively low compared to previous hammer prices.

5. Recent Trends: In the most recent auctions, hammer prices have varied, but there are examples of coins with similar conditions that have reached hammer prices of 210 euros or more.

Based on these factors, an estimated maximum purchase price for the coin could be in the range of 200 to 250 euros, considering that the condition is good and there are precedents of higher hammer prices in the past.

Therefore, a reasonable estimated maximum purchase price could be 250 euros.