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

1. Coin Condition: The coin has a condition rating of 95 (S/C-), indicating that it is in very good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction History:
- The average hammer price for similar coins has been 281.39 euros.
- In previous auctions, coins with a similar condition (95) have reached hammer prices that vary, but some examples are:
- 305 euros (2020-12-15)
- 400 euros (2020-07-02)
- 270 euros (2018-12-11)
- 320 euros (2023-03-16)

3. Starting Price: The starting price is 250 euros, which is a good starting point.

4. Recent Trends: In the most recent auctions, the hammer price has been in a range of 306 to 420 euros for coins of similar condition.

Based on these factors, an estimated maximum purchase price could be in the range of 350 to 400 euros. This is because, given the hammer price history and the good condition of the coin, it is reasonable to expect that bidders would be willing to pay a price in that range.

Therefore, an estimated maximum purchase price could be 400 euros.