To estimate a maximum purchase price for the coin in question, we can analyze the provided data and 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. Previous Prices:
- In the auction on 2020-11-19, a coin with a condition of 85 sold for 280 euros.
- In the auction on 2020-10-21, the same coin with a condition of 70 sold for 170 euros.
- In 2017, the hammer price was 160 euros, although the condition is not specified.
- In 2014, the hammer price was 380 euros, but the condition is not specified.

3. Starting Price and Average Hammer Price: The current starting price is 170 euros, and the average hammer price in the past has been 246 euros.

4. Sales Trends: The coin has been auctioned 5 times and has sold on all occasions, indicating a consistent interest in the coin.

Based on this data, we can make an estimation. Given that the current condition is 70, and considering that it previously sold for 170 euros in a similar auction, a reasonable hammer price could be in the range of 170 to 250 euros, depending on the demand in the current auction.

Estimated Maximum Purchase Price: Taking all these factors into account, an estimated maximum purchase price could be around 250 euros. This is based on the average hammer price and the condition of the coin.