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

1. Current Condition: The coin has a condition rating of 80 (MBC+), indicating that it is in fairly good shape. This suggests that its value should be in the upper range of previous auctions.

2. Auction History:
- The average hammer price in previous auctions is 282.37 euros.
- The last auction with a similar condition (80) had a hammer price of 240 euros.
- Overall, hammer prices have varied, but there are examples of sales exceeding 300 euros for coins with similar conditions.

3. Starting Price and Average Starting Price:
- The current starting price is 150 euros, which is below the average starting price of 166.75 euros. This may indicate that there is a buying opportunity at a reasonable price.

4. Price Trends:
- In previous auctions, coins with condition ratings of 80 have reached hammer prices ranging from 200 to 300 euros, with some exceptional cases exceeding 300 euros.

Based on these factors, an estimated maximum purchase price for this coin could be between 280 and 350 euros, considering that the condition is good and the price history suggests it could reach a higher value at auction.

Therefore, a reasonable maximum purchase price could be 350 euros.