To estimate a maximum purchase price for the coin in question, we can analyze the provided data:

1. Current Condition: The coin has a condition rating of 80 (MBC+), indicating that it is in quite good shape.

2. Auction History:
- The average hammer price in previous auctions is 36.79 euros.
- The last auction for this coin had a hammer price of 65 euros with a condition rating of 90, suggesting that a higher condition can lead to higher prices.
- In previous auctions, hammer prices have varied, but the range seems to be between 24 and 65 euros.

3. Starting Price: The current starting price is 30 euros, which is a good starting point.

4. Trends: Given that the coin has been auctioned 13 times and sold 12 of those times, there is good demand. Additionally, the fact that there are no scheduled auctions in the coming days may indicate that this is a unique opportunity for buyers.

Based on these factors, an estimated maximum purchase price could be in the range of 50 to 70 euros, considering that the condition is good and that the highest hammer price in the past was 65 euros. Therefore, a reasonable maximum purchase price could be 65 euros.