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 generally translates to a higher price compared to coins in lower condition.

2. Starting Price: The starting price is 100 euros. This is the baseline for the auction.

3. Sales History: The coin has been auctioned 22 times, of which it has sold 19 times. This indicates good demand and sustained interest in the coin.

4. Previous Prices: Looking at previous hammer prices, we can see that in recent auctions, the hammer prices have varied. For example, in the auction on 2024-05-27, the hammer price was 250 euros for a coin with a condition rating of 85. This suggests that there is potential for the coin to reach high prices in the future.

5. Average Hammer Price: The average hammer price of 92.79 euros is also a useful indicator, although the current coin's condition is better than average.

6. Price Trends: In the most recent auctions, hammer prices have shown an increase, which may indicate an upward trend in the value of this coin.

Taking all these factors into account, an estimated maximum purchase price could be in the range of 150 to 200 euros, considering that the condition is good and there is a history of hammer prices that supports this estimate. However, since the starting price is 100 euros, it is likely that bidders will be willing to pay more, especially if there is interest in the coin.

Therefore, a reasonable maximum purchase price could be 180 euros.