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

1. Current Condition: The coin has a condition of 75 (MBC), which indicates that it is in quite good shape. This suggests that its value should be in a higher range than coins with lower conditions.

2. Previous Prices: By looking at previous auction prices for coins with similar conditions (75-80), we can see that auction prices have varied, but there are examples of auctions reaching up to 280 euros for conditions of 80.

3. Average Auction Price: The average auction price for this coin is 142.39 euros, which provides a good reference.

4. Starting Price: The starting price is 75 euros, indicating that the seller expects a reasonable minimum price.

5. Recent Trends: In the most recent auctions, the hammer prices have been quite high, with examples reaching up to 550 euros for higher conditions.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 200 to 300 euros, considering its condition and previous auction prices. A more conservative price could be around 250 euros, given that it is a value that has been reached in recent auctions for coins of similar condition.