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

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

2. Historical Prices:
- The average hammer price in previous auctions is 399.08 euros.
- In past auctions, hammer prices have varied significantly, with a maximum price of 1200 euros for a condition of 95.
- The trend shows that coins with similar conditions (75) have had hammer prices ranging between 240 and 550 euros.

3. Starting Price and Average Starting Price:
- The current starting price is 350 euros, which is slightly higher than the average starting price of 265 euros.
- This suggests that the seller has expectations of a higher price, possibly due to demand or the quality of the coin.

4. Recent Trends: In the most recent auctions, hammer prices for coins with similar conditions have been in the range of 420 to 550 euros.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 450 to 600 euros. This range takes into account the current condition, historical hammer prices, and market trends.