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 (MS-), which is a medium level. This suggests that its value will not be as high as that of coins in better condition.

2. Previous Prices: By looking at the auction prices of coins with a similar condition (70), we can see that they have ranged between 130 and 220 euros in previous auctions. For example:
- In 2020, a coin with a condition of 70 was sold for 220 euros.
- In 2020, another coin with the same condition was sold for 170 euros.
- In 2023, a coin with a condition of 70 was sold for 190 euros.

3. Starting Price and Average Hammer Price: The current starting price is 200 euros, and the average hammer price for similar coins is 166.4 euros. This suggests that the starting price is relatively high compared to the average hammer price.

4. Recent Trends: In the most recent auctions, the hammer prices for coins with a condition of 70 have shown a range of 180 to 220 euros.

5. Competition in the Auction: Given that there are 3 similar coins that will be auctioned in the coming days, this could affect demand and, therefore, the hammer price.

Taking all these factors into account, an estimated maximum purchase price for this coin could be around 220 euros, which reflects both the condition and previous hammer prices as well as the current market situation.