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

1. Condition: The coin to be auctioned has a condition of 95 (EBC+), 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 coins with a similar condition (95) has been notably high, with a hammer price of 1300 euros in a previous auction.
- The price trend for coins with conditions of 85 and 80 also shows that prices can vary, but generally remain above the starting price.

3. Starting Price and Previous Prices:
- The current starting price is 300 euros, which is reasonable compared to the average starting price of 261.67 euros.
- The average hammer price of 489.56 euros suggests that there is significant potential for the coin to sell at a higher price.

4. Analysis of Previous Prices:
- In previous auctions, hammer prices have varied, but generally, coins with a condition of 95 have reached hammer prices exceeding 1000 euros in some cases.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 800 to 1200 euros, considering that the condition is high and the auction history shows significant potential for elevated hammer prices.

Therefore, a reasonable estimated maximum purchase price could be 1000 euros.