To estimate a maximum purchase price for the coin that will be auctioned, we will consider several factors:

1. Condition of the coin: The coin has a condition rating of 95 (S/C-), indicating that it is in very good shape. This generally translates to a higher price compared to coins with lower condition ratings.

2. Starting price: The starting price is 900 euros. This is the baseline for the auction.

3. Price history: By looking at previous auction prices for coins with a similar condition (95), we find that they have sold for prices that vary considerably in the past. For example:
- In 2020, a coin with a condition of 95 was auctioned for 1000 euros.
- In 2014, another coin with the same condition sold for 1100 euros.

4. Average hammer price: The average hammer price for this coin is 187.02 euros, but this may not be representative due to the high condition of the coin in question.

5. Auction trends: Since the coin has been auctioned 72 times and sold 56 times, there is good demand for this coin, which may drive up its price.

Based on these factors, an estimated maximum purchase price could be between 1000 and 1200 euros, considering that the condition is high and there are precedents for sales in that range. Therefore, a reasonable maximum purchase price could be 1100 euros.