To estimate a maximum purchase price for the coin in question, 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 conditions.

2. Current listing price and previous prices: The current listing price is 600 euros. In previous auctions, we have seen hammer prices that vary significantly, but there are examples of coins with similar conditions that have sold for higher prices. For instance, in 2015, a coin with a condition of 95 was sold for 346 euros, and in 2023, another with the same condition sold for 420 euros.

3. Price trends: The average hammer price for similar coins is 109.69 euros, but this may not reflect the true value of a coin in excellent condition like the one we are considering.

4. Supply and demand: The coin has been auctioned 102 times in the past, with a high sales percentage (91 out of 102). This suggests that there is consistent interest in this coin, which may increase its value.

5. Comparison with previous hammer prices: By observing the hammer prices of coins with similar conditions, we can see that the price range can be quite broad, but coins in exceptional condition tend to reach higher prices.

Taking all these factors into account, an estimated maximum purchase price for this coin could be between 800 and 1000 euros, given its condition and the price trends in previous auctions. This would allow for competitive bidding without exceeding a reasonable limit based on the price history.