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 rating of 70 (VF-). This is an important factor, as coins in better condition tend to fetch higher prices.

2. Starting Price and Average Hammer Price: The starting price is 70 euros, and the average hammer price in previous auctions is 143.02 euros. This suggests that, on average, similar coins have sold for a significantly higher price than their starting price.

3. Sales History: The coin has been auctioned 53 times, of which 49 have resulted in sales. This indicates good demand and consistent interest in the coin.

4. Previous Prices: Looking at previous hammer prices for coins with a similar condition (70), we can see that they have reached prices of up to 220 euros in recent auctions.

5. Recent Trends: In the most recent auctions, hammer prices have shown a trend of being higher, which could indicate an increase in demand or in the coin's value.

Based on these factors, an estimated maximum purchase price could be in the range of 180 to 220 euros, considering that the average hammer price is 143.02 euros and that there are examples of recent sales that have exceeded 200 euros.

Therefore, a reasonable maximum purchase price could be 200 euros.