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

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

2. Auction History:
- The average hammer price in previous auctions is 317.79 euros.
- The coin has been auctioned 16 times, of which it has sold 15 times, indicating good demand.
- Previous hammer prices for similar conditions (70-80) have ranged between 259 and 320 euros.

3. Starting Price and Estimates:
- The current starting price is 350 euros, with an estimated price of 600 euros. This suggests that the auctioneers have high expectations, but it may also indicate that the hammer price might not reach that figure.

4. Recent Trends: In the most recent auction (2024-02-27), the starting price was 350 euros with an estimated price of 600 euros, suggesting that there is growing interest in this coin.

Based on these factors, a reasonable maximum purchase price could be in the range of 400 to 450 euros, considering that the condition is good and there is a history of hammer prices that supports this estimate. However, since the starting price is 350 euros, buyers may be willing to pay a little more, but not enough to reach the estimated price of 600 euros.

Therefore, an estimated maximum purchase price could be 450 euros.