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

1. Current 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 9 times and has sold on all occasions, indicating good demand.
- The average hammer price in previous auctions is 24.33 euros, providing a solid basis for estimating its value.

3. Previous Prices:
- In the most recent auction (2023-05-23), the coin sold for 45 euros with a condition of 95.
- In another recent auction (2023-02-16), it sold for 65 euros, also with a condition of 95.

4. Starting Price: The current starting price is 12 euros, which is relatively low compared to previous hammer prices.

Based on this data, the maximum purchase price could be estimated by considering the highest hammer price in the past (65 euros) and the average hammer price (24.33 euros). Given the high condition and a history of successful sales, a reasonable maximum purchase price could be in the range of 50 to 70 euros.

Therefore, an estimated maximum purchase price could be 65 euros.