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

1. Current Condition: The coin has a condition rating of 75 (MBC), indicating that it is in an acceptable state, but not among the best qualities. This can influence the price, as coins in better condition tend to fetch higher prices.

2. Previous Auction Prices:
- The coin has had a maximum hammer price of 10,500 euros in a recent auction (2024-03-14) with a condition rating of 85.
- In other auctions, hammer prices have ranged between 7,000 and 9,000 euros, depending on the condition.

3. Starting Price and Average Hammer Price:
- The current starting price is 9,000 euros, which is higher than the average starting price of 7,000 euros in previous auctions.
- The average hammer price is 9,500 euros, suggesting that buyers are willing to pay close to this price.

4. Sales Trends: The coin has sold in 7 out of the last 8 auctions, indicating consistent interest in the coin.

Based on these factors, an estimated maximum purchase price could be in the range of 9,000 to 10,000 euros. Given that the current condition is 75, it is reasonable to consider a hammer price that does not exceed the highest hammer price of 10,500 euros, while also taking the condition into account.

Therefore, an estimated maximum purchase price could be 10,000 euros. This reflects a balance between the current condition and previous hammer prices.