To estimate a maximum purchase price for the coin in question, we can analyze the provided data, especially the current grade of the coin (85, ebc-) and the hammer prices from previous auctions.

1. Grade: The coin has a grade of 85, indicating that it is in quite good condition. In the past, coins with similar grades have reached hammer prices that varied considerably.

2. Previous hammer prices:
- In previous auctions, coins with grades of 70 and 80 have reached hammer prices of up to 190 and 320 euros, respectively.
- The last auction with a grade of 80 had a hammer price of 190 euros, suggesting that a grade of 85 could justify a higher hammer price.

3. Average hammer price: The average hammer price for this coin is 149.63 euros, which can also serve as a reference.

4. Price trends: Observing the starting and hammer prices, it seems that coins tend to sell for above their starting price, especially in higher grades.

Based on these points, an estimated maximum purchase price for the coin with a grade of 85 could be in the range of 200 to 250 euros, considering that coins in similar conditions have reached hammer prices of up to 320 euros in the past.

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