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

1. Condition: The coin has a condition rating of 95 (EF+), indicating that it is in very good shape. This generally increases its value compared to coins with lower conditions.

2. Auction history: The coin has been auctioned 12 times and has sold on all occasions. This suggests a consistent demand and interest in the coin, which can positively influence its price.

3. Previous hammer prices: The previous hammer prices for coins with a similar condition (95) have been:
- 420 € (2021)
- 560 € (2024)
- 550 € (2023)
- 550 € (2024)
- 650 € (2024)

These prices indicate that, in recent auctions, the coin has reached hammer prices ranging from 420 € to 650 €.

4. Current starting price: The starting price is 500 €, which is a good indicator that the seller expects a competitive price.

5. Average hammer price: The average hammer price for this coin is 413.5 €, which is also a relevant figure.

Taking all these factors into account, an estimated maximum purchase price could be positioned within the range of the highest hammer prices observed in recent auctions. Given that the highest hammer price has been 650 €, and considering that the coin is in good condition, a reasonable maximum purchase price could be:

Estimated maximum purchase price: 650 €

This price reflects the trend of recent hammer prices and the good condition of the coin. However, it is always advisable to stay alert to the dynamics of the auction and the competition from other bidders.