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

1. Condition of the coin: The coin to be auctioned has a condition rating 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 this coin in the past is 234.03 euros.
- The last auction of this coin with a similar condition (95) had a hammer price of 220 euros.
- In previous auctions, hammer prices have varied, but the highest values have reached up to 1100 euros in exceptional cases.

3. Starting price: The starting price of 300 euros is a good indicator of the seller's expectations, but it does not necessarily reflect the final hammer price.

4. Price trends: By observing the hammer prices of coins with similar conditions, it seems that the price range can fluctuate between 200 and 350 euros, depending on the demand at the time of the auction.

Based on these factors, an estimated maximum purchase price for this coin could be around 350 euros, considering that the condition is high and that the price history shows it can reach higher values in competitive auctions. However, it is important to take into account the market dynamics at the time of the auction, as demand can influence the final price.