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 80 (MBC+), indicating that it is in relatively good shape. This suggests that its value should be above that of coins in worse conditions.

2. Auction History:
- The average hammer price for similar coins has been 53.44 euros.
- In previous auctions, coins with similar conditions (around 80) have reached hammer prices of up to 70 euros (in the case of a coin with a condition of 85).
- The most recent auction of a coin with a condition of 90 had a hammer price of 50 euros, indicating that value can vary significantly with condition.

3. Starting Price and Estimates:
- The starting price of 30 euros is reasonable, given that the average starting price for similar coins is 26.93 euros.
- The coin has been sold in the past at prices that varied, but the range seems to be between 9 and 70 euros, depending on the condition.

4. Market Trends: Since there are two auctions scheduled in the coming days, this could increase competition and, therefore, the hammer price.

Based on these factors, an estimated maximum purchase price for the coin with a condition of 80 (MBC+) could be in the range of 60 to 75 euros. This is based on the auction price history and the current condition, as well as the trend that prices may increase in competitive auctions.