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

1. Coin Condition: The coin being auctioned 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 conditions.

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

3. Price History: By looking at previous auction prices for similar coins, we can see that prices have varied considerably. For example, in past auctions, coins with similar conditions have reached hammer prices ranging from 18 euros to 900 euros, depending on demand and other factors.

4. Average Hammer Price: The average hammer price for this particular coin is 123.72 euros, suggesting that, in general, coins of this reference tend to sell for a considerably lower price than the current starting price.

5. Recent Trends: In the most recent auctions, we have seen hammer prices that can be significantly higher than the average price, especially for coins in similar conditions.

Given all this, an estimated maximum purchase price could be calculated considering that the hammer price may be higher than the starting price, especially for a coin in such good condition.

Estimation: Based on the price history and condition, a reasonable maximum purchase price could be in the range of 800 to 1000 euros, assuming there is sufficient interest in the coin and that the auction attracts buyers willing to compete for it.