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

1. Coin Condition: The coin has a condition of 70 (MS-), indicating that it is in an acceptable state, but not of the highest quality.

2. Previous Auction Prices: By observing the hammer prices of coins with similar conditions (around 70), we can see that the hammer prices have varied. For example:
- In 2023, a coin with a condition of 70 was sold for 460 euros.
- In other auctions, hammer prices for similar conditions have ranged from 50 to 120 euros.

3. Average Hammer Price: The average hammer price for this coin is 114.43 euros, which can serve as a good indicator of the expected value.

4. Starting Price: The starting price is 50 euros, suggesting that the seller expects a reasonable minimum price.

5. Auction Trends: The coin has been auctioned 35 times, of which 32 have sold, indicating good demand.

Based on these factors, an estimated maximum purchase price could be in the range of 120 to 150 euros, considering that the condition is acceptable and there is a history of hammer prices that supports this estimate.

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