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), which indicates that it is in fairly good shape, but not the best possible condition.

2. Historical Prices: By looking at previous auction prices for coins with similar conditions, we can see that the hammer prices have varied. For example:
- In past auctions, coins with conditions ranging from 70 to 80 have had hammer prices between 220 and 300 euros.
- The last auction of a coin with a condition of 95 reached a hammer price of 500 euros, indicating that coins in better condition can fetch significantly higher prices.

3. Starting Price and Average Price: The current starting price is 350 euros, and the average hammer price in the past has been 278.38 euros. This suggests that the starting price is relatively high compared to the average hammer price.

4. Recent Trends: In the most recent auctions, hammer prices have shown a trend of increasing, especially for coins in good condition.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 300 to 400 euros. This is because, although the starting price is 350 euros, the condition of 75 suggests that the hammer price should not significantly exceed the starting price unless there is exceptional demand.

Therefore, a reasonable maximum purchase price could be 400 euros.