To estimate a maximum purchase price for the coin in question, we can analyze 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 for this coin in the past is 242 euros.
- The last auction of this coin with a similar condition (75) had a hammer price of 170 euros in 2019.
- In previous auctions, hammer prices have varied, but generally, they have ranged from 130 to 900 euros, depending on condition and demand.

3. Starting Price and Estimates:
- The current starting price is 175 euros, which is slightly higher than the average starting price of 158.57 euros.
- The estimated price for this auction is 250 euros, suggesting that there are expectations for the coin to sell at a higher price.

4. Recent Trends: In the most recent auctions, hammer prices have been quite high, which could indicate an increase in demand or the value of the coin.

Based on these factors, an estimated maximum purchase price could be around 300 euros. This price takes into account the current condition, the auction price history, and the auction expectations. However, it is important to keep in mind that the market can be volatile, and the final decision should be based on personal evaluation and willingness to pay.