To estimate a maximum purchase price for the coin in question, we can analyze several factors:

1. Current Condition: The coin has a condition of 70 (MS-). This is an important factor, as coins in better condition tend to reach higher prices.

2. Starting Price and Average Hammer Price: The starting price is 120 euros, and the average hammer price in previous auctions is 162.61 euros. This suggests that, in general, coins of this reference tend to sell for above their starting price.

3. Auction History: By observing the hammer prices of previous auctions for coins with similar conditions (70 and 75), we can see that they have reached hammer prices that vary, but are generally in the range of 145 to 240 euros. For example, in the 2020 auction, a coin with a condition of 70 was sold for 145 euros.

4. Recent Trends: In the most recent auctions, the hammer price for coins with a condition of 70 has been around 160 euros, indicating that interest and value for these coins remain steady.

Based on these factors, an estimated maximum purchase price could be in the range of 160 to 200 euros. This is because the average hammer price is 162.61 euros, and considering that interest in the coin may lead to a higher price at auction.

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