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

1. Current Condition: The coin has a condition rating of 75 (MBC), which indicates that it is in fairly good shape, but not among the best qualities.

2. Auction History:
- The average hammer price for this coin is 315.21 euros.
- In previous auctions, we have seen hammer prices that varied significantly, with some reaching up to 1300 euros in exceptional conditions (such as in the auction on 2022-03-17 with a condition of 95).
- The majority of hammer prices for similar conditions (75-80) have been in the range of 200 to 500 euros.

3. Starting Price: The current starting price is 250 euros, which is a reasonable starting point.

4. Recent Trends: In the most recent auctions, hammer prices for coins with similar conditions have been in the range of 300 to 500 euros.

Based on these factors, an estimated maximum purchase price for this coin, considering its condition and price history, could be between 400 and 500 euros. This aligns with the range of hammer prices that have been observed for coins in similar conditions in the past.

Therefore, a reasonable maximum purchase price could be 450 euros.