To estimate a maximum purchase price for the coin in question, we can consider several factors based on the provided data:

1. Current Condition: The coin has a condition rating of 75 (MBC), indicating a medium-low quality. This may influence the price, as coins in better condition tend to fetch higher prices.

2. Current Starting Price and Previous Prices: The current starting price is 125 euros. In previous auctions, the average hammer price has been 228.52 euros, suggesting that, in general, coins of this reference tend to sell for a price higher than the starting price.

3. Sales History: Out of the 38 times it has been auctioned, it has sold on 34 occasions, indicating good demand. Additionally, the highest recorded hammer price was 900 euros, although this may have been for a coin in better condition.

4. Recent Trends: In the most recent auctions, hammer prices have varied, but there are examples of coins with similar conditions that have sold for prices around 200-300 euros.

5. Estimation Based on Condition: Given that the condition of this coin is 75, it is reasonable to expect that the hammer price will be below the overall average, but it could still reach a competitive price.

Taking all these factors into account, an estimated maximum purchase price for this coin could be between 200 and 250 euros. This is based on the hammer price history and the current condition of the coin.