Based on the provided data, we can conduct an analysis to estimate a maximum purchase price for the coin in question.

1. Starting price: 2500 euros.
2. Average hammer price in the past: 4400 euros.
3. Condition of the coin: 95 (S/C-), which is a high condition.
4. Auction history: It has been auctioned once before, with an estimated price of 3000 euros and a hammer price of 4400 euros.

Given that the coin is in high condition and has reached a hammer price of 4400 euros in the past, it is reasonable to consider that interest in this coin could be similar in the upcoming auction.

Additionally, the fact that there have been no failed sale attempts in the past suggests that there is solid interest in this coin.

Estimation of the maximum purchase price:
- Considering the previous average hammer price (4400 euros) and the current starting price (2500 euros), a maximum purchase price could be set in a range between the average hammer price and a bit more, given that the condition is high and there is interest in the coin.

Therefore, an estimated maximum purchase price could be approximately 4500 to 4800 euros. This allows for a margin for competition in the auction, given the price history and the condition of the coin.