To estimate a maximum purchase price for the coin in question, we can consider several factors based on the provided data:

1. Current Condition: The coin has a condition rating of 85 (ebc-), indicating that it is in quite good shape. This generally translates to a higher value compared to coins with lower conditions.

2. Starting Price and Average Hammer Price: The starting price is 1200 euros, and the average hammer price in previous auctions is 1047.22 euros. This suggests that, although the starting price is high, the hammer price tends to be lower.

3. Auction History: In the auction history, it is observed that the coin has had hammer prices that vary significantly, but overall, the hammer prices have been below the current starting price. For example, in the auction on 2024-03-14, the hammer price was 2300 euros, but in other auctions, the prices have been lower.

4. Price Trends: The average starting price of 510 euros and the average hammer price of 1047.22 euros indicate that, while there is interest in the coin, the market may not be willing to pay the current starting price of 1200 euros.

5. Comparison with Previous Prices: The most recent auction shows a starting price of 1200 euros with an estimated price of 2500 euros, suggesting that there are expectations of a higher value, but this does not always translate into an actual hammer price.

Taking all these factors into account, an estimated maximum purchase price could be positioned in a range between the average hammer price and the starting price, considering the condition and market interest.

Estimated Maximum Purchase Price: It may be reasonable to estimate a maximum purchase price of around 1500 to 1800 euros. This allows for some competition in the auction while also staying within a range that reflects the history of hammer prices.