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

1. Coin Condition: The coin has a condition rating of 70 (MS-), indicating that it is in relatively good shape, but not of the highest quality (PR).

2. Auction History:
- The average hammer price for similar coins has been 100.37 euros.
- In previous auctions, coins with a similar condition (70) have reached hammer prices that vary, but some examples are:
- 60 euros (2020-12-15)
- 70 euros (2019-12-10)
- 75 euros (2020-09-17)
- 80 euros (2022-10-18)
- 130 euros (2023-02-16)

3. Starting Price: The starting price is 40 euros, which may attract more bidders.

4. Price Trends: Observing the trends, it seems that the hammer price for coins in similar conditions has been increasing, especially in recent years.

Based on these factors, an estimated maximum purchase price could be between 120 and 150 euros, considering that the average hammer price is 100.37 euros and that there are examples of higher hammer prices for coins in similar conditions.

Therefore, a reasonable maximum purchase price could be 150 euros.