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

1. Current Condition: The coin has a grade of 70 (MS-), indicating that it is in acceptable condition, but not among the best qualities. This may influence the price, as coins in better condition tend to reach higher prices.

2. Historical Prices: Looking at previous auction results, the coin has reached hammer prices that varied, but generally, hammer prices for similar grades (70) have been around 800 to 1100 euros in past auctions. The highest recorded price for a grade of 70 was 1100 euros.

3. Current Starting Price: The starting price of 1400 euros is higher than previous hammer prices for similar grades. This may indicate that the seller expects greater interest in this auction, but it could also result in the coin not selling if bidders are not willing to pay that price.

4. Market Trends: The average hammer price in the past has been 1106.19 euros, suggesting that, in general, buyers are willing to pay around this amount for coins of similar quality.

5. Auction Expectations: Given that there is an auction scheduled in the coming days, bidders may be more willing to compete for the coin, especially if there is growing interest in coins of this reference.

Based on these factors, an estimated maximum purchase price could be around 1100-1200 euros. This is based on the highest recorded hammer price for a similar grade and the average hammer price. However, given the starting price of 1400 euros, bidders may be cautious and not willing to pay that much, so a price of 1200 euros could be a reasonable limit for a bid.