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

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

2. Starting Price and Previous Prices: The current starting price is 90 euros. In previous auctions, the average hammer price has been 162.08 euros, suggesting that coins of this reference tend to sell for significantly higher prices than their starting price.

3. Price Trends: By observing the hammer prices of previous auctions for coins with a similar condition (85), we can see that they have reached hammer prices that vary, but in many cases exceed 200 euros. For example, in previous auctions, coins with a condition of 85 have sold for hammer prices of 290 euros and 270 euros.

4. Demand and Supply: The coin has been auctioned 82 times, with a high sales percentage (78 out of 82). This indicates a consistent interest in this coin, which may increase its value at auction.

Taking all these factors into account, an estimated maximum purchase price for this coin could be between 200 and 250 euros, considering that the average hammer price has been 162.08 euros and that there are examples of previous sales exceeding 200 euros.

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