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 214.09 euros.
- The last auction with a similar condition (75) had a hammer price of 300 euros.
- Overall, hammer prices have varied, but there are examples of sales exceeding 300 euros.

3. Starting Price: The starting price is 300 euros, indicating that the seller has high expectations for this auction.

4. Price Trends: Looking at previous hammer prices, it seems there is consistent interest in this coin, and prices have shown a trend of increasing in recent auctions.

Based on these factors, an estimated maximum purchase price could be around 350-400 euros. This is because, although the starting price is 300 euros, the auction history and current condition suggest that there may be competition in the auction, which could lead to a higher hammer price.