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

1. Condition: The coin has a condition rating of 80 (MS+), 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 in previous auctions is 25.16 euros.
- In recent auctions, the hammer price has ranged between 20 and 45 euros, depending on the condition and demand at that time.
- The last auction with a similar condition (80) had a hammer price of 45 euros.

3. Starting price and demand: The current starting price is 25 euros, which is slightly higher than the average starting price of 17.97 euros. This may indicate higher demand or specific interest in this coin.

4. Sales trends: Out of the 30 times it has been auctioned, it has sold 27 times, suggesting there is consistent interest in this coin.

Taking all these factors into account, an estimated maximum purchase price could be around 40-45 euros, as this is a price that has been reached in previous auctions with a similar condition and reflects the current market price trends.