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

1. Current Condition: The coin has a condition rating of 85 (ebc-), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Previous Auction Prices: By observing previous auction prices for coins with a similar condition (85), we can see that they have reached auction prices that vary significantly. For example, in past auctions, coins with a condition of 85 have reached auction prices of up to 360 euros.

3. Average Auction Price: The average auction price for this coin is 142.2 euros, which provides a useful benchmark.

4. Starting Price: The current starting price is 125 euros, suggesting that the seller has reasonable expectations for an auction price.

5. Recent Trends: In the most recent auctions, auction prices have shown a trend of increasing, especially for coins in good condition.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 200 to 300 euros, considering that the condition is good and there are precedents for higher auction prices in the past. However, since the starting price is 125 euros, it is likely that buyers will be willing to pay a bit more, but not necessarily up to the historical maximum.

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