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

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. Previous Auction Prices:
- The coin has had a hammer price of 370 euros in a recent auction with a condition of 70.
- In other auctions, coins with similar conditions have reached hammer prices of up to 480 euros.

3. Average Hammer Price: The average hammer price for this coin is 415.33 euros, indicating that, in general, buyers are willing to pay around this amount.

4. Starting Price: The starting price is 300 euros, suggesting that there is room for the hammer price to be higher than this.

5. Auction Trends: The coin has been auctioned 16 times, of which 12 have been sold. This indicates a consistent interest in the coin, which may influence the price.

Based on these factors, an estimated maximum purchase price could be between 450 and 480 euros, considering that condition is a key factor and that the hammer price in previous auctions with similar conditions has reached those levels.

Therefore, a reasonable maximum purchase price could be 480 euros.