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 translates to a higher price compared to coins in lower condition.

2. Previous auction prices:
- The average hammer price for this coin has been 3308.8 euros.
- In previous auctions, hammer prices have varied, but several have exceeded 3000 euros, even reaching up to 4800 euros in a recent auction.

3. Starting price: The current starting price is 2800 euros, which is a good starting point, but given the history of hammer prices, it is likely that the final price will be higher.

4. Auction trends: The coin has been auctioned 22 times, with a sell-through rate of 95.45% (21 out of 22 auctions). This suggests that there is consistent interest in this coin, which may increase its value at auction.

5. Previous price estimates: In past auctions, the estimated price has been as high as 5000 euros, indicating that there is potential for the hammer price to be high.

Taking all these factors into account, an estimated maximum purchase price could be around 4000-4500 euros, as this range aligns with previous hammer prices and the good condition of the coin. However, it is important to consider that the final price may vary depending on competition in the auction and the interest of other buyers.