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

1. Current Condition: The coin has a condition rating of 80 (MBC+). This is an important factor, as coins in better condition tend to fetch higher prices at auctions.

2. Previous Auction Prices:
- The average hammer price for this coin in previous auctions is 2943.75 euros.
- In the 2022 auction, the coin sold for 7500 euros with a condition rating of 95, indicating that coins in better condition can reach significantly higher prices.
- In the 2024 auction, the same coin was hammered at 3000 euros with a condition rating of 80, which is relevant for our estimation.

3. Starting Price and Average Starting Price:
- The current starting price is 1500 euros, which is below the average starting price of 1661.11 euros. This suggests that the starting price is reasonable and could attract more bidders.

4. Sales Trends: The coin has been auctioned 9 times, of which it has sold 8 times. This indicates a consistent interest in the coin, which may influence the hammer price.

Based on these factors, an estimated maximum purchase price could be in the range of 2500 to 3000 euros, considering that the condition is 80 and that in previous auctions it has reached hammer prices of up to 3000 euros under similar conditions.

Therefore, a reasonable maximum purchase price could be approximately 2800 euros.