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 relatively good shape, but not among the highest quality.

2. Auction History:
- The average hammer price for similar coins is 151.08 euros.
- In previous auctions, we have seen hammer prices that varied significantly, ranging from 40 euros to 650 euros, depending on the condition and demand at that time.

3. Starting Price and Average Starting Price:
- The current starting price is 65 euros, which is below the average starting price of 86.92 euros. This could indicate a buying opportunity at a reasonable price.

4. Recent Trends: In the most recent auctions, hammer prices have been higher, especially for coins in good condition. For example, in the March 2023 auction, a similar coin sold for 380 euros.

5. Selling Expectations: Given that there is an auction scheduled in the coming days, demand may increase, which could drive up the hammer price.

Taking all these factors into account, an estimated maximum purchase price for this coin could be between 150 and 200 euros. This is based on the average hammer price and the price trend for coins of similar condition. However, it is important to be aware of the competition in the auction, as this may influence the final price.