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), which indicates that it is in fairly good shape, but not among the best qualities (FDC).

2. Auction History:
- The average hammer price for coins with a similar condition (75) in the past has been approximately 300 euros.
- In previous auctions, we have seen hammer prices that varied, but there are examples of coins with conditions of 75 that have sold for around 300-360 euros.

3. Starting Price and Average Hammer Price:
- The current starting price is 350 euros, which is slightly higher than the average hammer price of 333.92 euros.
- However, the average starting price of 250.98 euros suggests that there is room for the hammer price to be higher.

4. Recent Trends: In the most recent auctions, hammer prices have been in the range of 270 to 500 euros for similar conditions, indicating that there is growing interest in this coin.

5. Analysis of Previous Prices:
- The coin has had a hammer price of up to 420 euros in a previous auction with a condition of 95, suggesting that interest may increase with better condition.

Based on these factors, an estimated maximum purchase price for this coin, considering its current condition and price history, could be in the range of 360 to 400 euros. This allows for some margin for competition in the auction, given that the starting price is 350 euros.