To estimate a maximum purchase price for the coin in question, we can analyze the provided data, especially the previous auction prices and the current condition of the coin.

1. Current Condition: The coin has a condition of 70 (VF-). This indicates that it is in an acceptable state, but not of high quality.

2. Previous Auction Prices: By observing the auction prices of coins with similar conditions (70-75), we can see that the auction prices have varied. For example:
- In previous auctions, coins with a condition of 70 have reached auction prices ranging from 60 to 150 euros.
- The average auction price for coins with similar conditions seems to be around 85-100 euros.

3. Average Auction Price: The average auction price for this particular coin has been 136.65 euros, suggesting that there is considerable interest in this coin.

4. Starting Price: The starting price is 75 euros, which is reasonable given the price history.

5. Recent Trends: In the most recent auctions, the auction prices have shown a range that can go from 70 to 220 euros, depending on demand and condition.

Based on these factors, an estimated maximum purchase price for this coin, considering its condition and market interest, could be in the range of 150 to 180 euros. This allows for a margin for competition in the auction and reflects the historical value of the coin in similar conditions.