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

1. Current Condition: The coin has a condition rating of 70 (MS-), indicating that it is in an acceptable state, but not among the best qualities.

2. Auction History:
- The average hammer price for coins of similar condition (70) has been approximately 124.25 euros.
- In previous auctions, hammer prices for coins with a condition of 70 have varied, reaching up to 130 euros in 2020 and 135 euros in 2020.

3. Starting Price: The current starting price is 100 euros, which may influence bidder interest.

4. Price Trends: Observing previous hammer prices, it seems there is potential for the coin to sell above the starting price, especially if there is interest in the auction.

5. Market Factors: Since there are no auctions scheduled in the coming days, this could increase interest in this particular auction.

Taking all these factors into account, an estimated maximum purchase price could be around 130-140 euros, considering that this is a price that has been reached in previous auctions for coins of similar condition and that interest could be high.