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

1. Current Condition: The coin has a condition of 70 (VF-). This is an important factor, as coins in better condition tend to reach higher prices.

2. Auction History:
- The coin has been auctioned 14 times, of which it has sold 13 times. This indicates good demand.
- Previous hammer prices varied, but there are examples of hammer prices reaching up to 1600 euros for conditions of 95.
- The trend of hammer prices for similar conditions (80-85) has been in the range of 500 to 800 euros.

3. Starting Price and Average Price:
- The current starting price is 300 euros, which is significantly lower than the average starting price of 638 euros and the average hammer price of 949.09 euros.

4. Comparison with Previous Prices:
- Looking at previous hammer prices for similar conditions, the lowest hammer price was 490 euros and the highest was 1600 euros. However, most hammer prices for conditions between 70 and 85 have been in the range of 500 to 800 euros.

Based on these factors, an estimated maximum purchase price for the coin, considering its condition and auction history, could be in the range of 600 to 800 euros. This aligns with previous hammer prices and the demonstrated interest in past auctions.