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 (70-80), we can see that:
- In several auctions, coins with a condition of 70 have reached hammer prices between 140 and 170 euros.
- The average hammer price for coins with a condition of 70 seems to be around 160 euros.

3. Average Hammer Price: The average hammer price for this particular coin is 163.23 euros, which reinforces the idea that the range of 140-170 euros is reasonable.

4. Starting Price: The starting price is 120 euros, which is a good starting point, but since the average hammer price is significantly higher, this suggests that there is potential for the hammer price to be greater.

5. Auction Trends: Given that the coin has sold on all previous occasions and has had a hammer price that exceeds the starting price, it is reasonable to expect that interest in the current auction will also be high.

Based on these points, an estimated maximum purchase price for this coin could be around 160-180 euros. This is based on the analysis of previous hammer prices and the current condition of the coin.