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 fairly good state, but not the best. This suggests that its value will not reach the highest prices seen for coins in better condition.

2. Auction History:
- The average hammer price for coins in similar condition (70) has been approximately 100-130 euros in previous auctions.
- In past auctions, hammer prices for coins with a condition of 70 have varied, but the range seems to be between 70 and 100 euros, with some exceptional cases reaching up to 150 euros.

3. Starting Price and Average Hammer Price:
- The current starting price is 40 euros, which is relatively low compared to the average hammer price of 328.83 euros for all auctions of this coin. However, the average starting price of 130.95 euros suggests that there is potential for an increase in the hammer price.

4. Recent Trends:
- In the most recent auctions, there has been an increase in hammer prices, which could indicate a rising trend in interest for this coin.

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 the final price.

Based on these factors, an estimated maximum purchase price for this coin could be between 100 and 150 euros. This reflects both the historical hammer prices for coins in similar condition and the current trend in the market.