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

1. Current Condition: The coin has a condition rating of 80 (MBC+), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction History:
- The average hammer price for this coin in the past is 36.22 euros.
- Previous hammer prices have varied, but there are examples of hammer prices of 75 euros (in 2020) and 50 euros (in 2021) for coins of similar or lower condition.

3. Starting Price: The current starting price is 30 euros, which is a good starting point. However, since the average hammer price is higher, it is reasonable to expect that the final hammer price will be higher.

4. Sales Trends: The coin has been auctioned 12 times, of which it has sold 10 times. This indicates good demand and sustained interest in the coin.

5. Comparison with Previous Prices: Looking at previous hammer prices, the highest was 75 euros, and the lowest was 16 euros. However, given that the current condition is 80, it is likely that the hammer price will be closer to the upper range.

Based on these factors, an estimated maximum purchase price could be between 50 and 75 euros. Given that the average hammer price is 36.22 euros and considering the condition, a reasonable maximum price could be approximately 60 euros. This allows for some margin for competition in the auction and reflects the historical interest in the coin.