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 quite good shape. This may positively influence its price.

2. Auction History:
- The average hammer price in previous auctions is 53.2 euros.
- The last auction where the coin was sold had a hammer price of 100 euros with a condition rating of 80, suggesting that coins in better condition can reach higher prices.
- In the 2022 auction, with a condition rating of 70, the hammer price was 40 euros, indicating that condition has a significant impact on price.

3. Starting Price and Estimates:
- The current starting price is 30 euros, which is below the average hammer price of previous auctions.
- The average starting price of 36.43 euros also suggests that the current starting price is competitive.

4. Supply and Demand: The coin has been auctioned 6 times in the past, of which it has sold 5 times. This indicates good demand, which may drive up the price.

Taking all these factors into account, an estimated maximum purchase price could be in the range of 60 to 80 euros. This is based on the auction price history and the current condition of the coin. A price of 70 euros could be a reasonable target, as it is above the average hammer price and reflects the good condition of the coin.