To estimate a maximum purchase price for the coin in question, we can 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 average hammer price in previous auctions is 274.16 euros.
- The last auction for this coin was sold for 460 euros (2023-01-31) with a condition of 85, indicating that coins in better condition can achieve significantly higher prices.
- Generally, hammer prices for coins with similar condition (70) have ranged from 240 to 340 euros in previous auctions.

3. Starting Price: The current starting price is 275 euros, which is a good starting point.

4. Recent Trends: The price trend seems to be increasing, especially in the most recent auctions, where higher prices have been reached.

Based on these factors, an estimated maximum purchase price for the coin with a condition of 70 could be in the range of 300 to 350 euros, considering that the highest hammer price in the past was 460 euros for a better condition.

Therefore, a reasonable maximum purchase price could be 350 euros.