To estimate a maximum purchase price for the coin in question, we will 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. Starting Price: The starting price is 120 euros. This sets a baseline for the auction.

3. Sales History:
- The average hammer price in previous auctions is 121.93 euros.
- 78 out of 86 times it has been auctioned, indicating good demand.
- In previous auctions, hammer prices have varied, but there are examples of hammer prices exceeding 150 euros for coins with similar conditions.

4. Previous Prices:
- In past auctions, coins with conditions of 70 have reached hammer prices of up to 130 euros.
- The last auction with a hammer price of 200 euros for a coin with a condition of 70 suggests there is potential for higher prices.

5. Recent Trends: The price trend appears to be increasing, with some recent auctions exceeding 150 euros.

Based on these factors, an estimated maximum purchase price for this coin could be between 150 and 180 euros, considering that interest in the coin may lead to competitive bidding. Therefore, a reasonable maximum purchase price could be 170 euros.