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

1. Current Condition: The coin has a condition of 70 (MS-). This is an important factor, as coins in better condition tend to reach higher prices.

2. Previous Prices: By observing previous auction prices for coins with similar conditions, we can see that:
- In past auctions with a condition of 70, the hammer prices have ranged between 780 and 1900 euros.
- The general trend seems to be that coins with a condition of 70 have reached hammer prices around 850 to 1200 euros on several occasions.

3. Starting Price and Average Hammer Price: The current starting price is 1450 euros, which is higher than the average hammer price of 1299.43 euros. This suggests that the seller has high expectations, but it may also indicate that the market is willing to pay more.

4. Recent Trends: In the most recent auctions, hammer prices have been in the range of 1350 to 1601 euros for similar conditions.

Based on these factors, an estimated maximum purchase price could be in the range of 1300 to 1600 euros, considering that the starting price is 1450 euros and that the market has shown a willingness to pay prices in that range for coins of similar condition.

Therefore, an estimated maximum purchase price could be 1600 euros.