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

1. Current Condition: The coin has a condition of 85 (ebc-), which indicates that it is in quite good shape. This is important because coins in better condition tend to fetch higher prices.

2. Starting Price and Average Hammer Price: The starting price is 90 euros, and the average hammer price in previous auctions is 96.18 euros. This suggests that, generally, coins of this reference tend to sell for above their starting price.

3. Sales History: In the past, similar coins have been auctioned with hammer prices that varied significantly. For example, in a 2020 auction, a coin with a condition of 85 sold for 110 euros. This indicates that there is potential for coins in similar conditions to reach higher prices.

4. Recent Trends: Looking at the most recent auctions, there are examples of coins that have sold for prices exceeding 100 euros, suggesting that interest in this coin may be increasing.

5. Comparison with Previous Prices: The coin has had a hammer price of up to 400 euros in exceptional conditions, but for a condition of 85, it is reasonable to expect a more moderate price.

Taking all these factors into account, an estimated maximum purchase price for this coin could be around 120-130 euros. This reflects a balance between the condition, sales history, and current interest in the coin.