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

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

2. Starting price: The starting price is 600 euros. This is the baseline for the auction.

3. Price history: By looking at previous hammer prices for coins with a similar condition (95), we can see that in the past, coins with this condition have reached hammer prices of up to 1200 euros (as seen in the auction on 2014-10-30).

4. Average hammer price: The average hammer price for this coin is 213.55 euros, but this may be influenced by coins of lower condition.

5. Recent trends: In the most recent auctions, hammer prices have varied, but there are examples of coins with similar condition that have reached significant hammer prices.

Taking these factors into account, an estimated maximum purchase price could be in the range of 1000 to 1200 euros, given that the condition is high and there are precedents for hammer prices in that range. However, since the starting price is 600 euros, it is likely that the final hammer price will not significantly exceed this range unless there is high demand for the coin at the auction.

Therefore, a reasonable estimated maximum purchase price could be 1000 euros.