To estimate a maximum purchase price for the coin in question, we can analyze the provided data, especially the previous auction prices and the condition of the auctioned coins.

1. Current starting price: 3000 euros.
2. Auction price history:
- The coin has had auction prices that vary significantly, from 47 euros to 3000 euros.
- The highest auction prices have been for coins in conditions of 90 and 95, which are quite good.
- The highest recorded auction price is 3000 euros, which corresponds to a starting price of 350 euros in a previous auction.

3. Condition: There is no information about the condition of this particular coin, making the estimation more uncertain. However, we can observe that coins with conditions ranging from 80 to 95 have had auction prices between 270 and 3000 euros.

4. Price trends:
- The average auction price in previous auctions is 721.38 euros, indicating that, in general, coins of this reference tend to sell for a considerably lower price than the current starting price of 3000 euros.
- The coin has been auctioned 23 times, of which 22 have sold, suggesting good demand.

5. Estimation: Given that the starting price is 3000 euros and considering the auction price history, a maximum estimated purchase price could be set at a more realistic range. Based on the average auction price and the highest prices reached in the past, a reasonable maximum purchase price could be approximately 1000 to 1500 euros, depending on the final condition of the coin.

Therefore, an estimated maximum purchase price could be 1500 euros.