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

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

2. Previous Auction Prices: By observing the hammer prices of coins with a similar condition (95), we can see that they have reached hammer prices of up to 1,400 euros in the past (as seen in the auction on March 8, 2018).

3. Starting Price and Average Prices: The current starting price is 450 euros, and the average hammer price in previous auctions is 128.83 euros. However, given that the condition of this coin is high, it is reasonable to expect that the hammer price will be significantly higher than the average.

4. Auction Trends: The coin has been auctioned 266 times, with an 86% sell-through rate (230 times sold). This suggests that there is consistent interest in this coin, which may increase its value.

5. Recent Hammer Prices: In recent auctions, the hammer prices for coins of similar condition have been high, suggesting that the market is willing to pay more for well-preserved coins.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 800 to 1,200 euros. This range takes into account the high condition, interest in the coin, and previous hammer prices for similar coins.