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 (MBC-), which indicates that it is in an acceptable state, but not among the best qualities. This can influence the price, as coins in better condition tend to reach higher prices.

2. Previous Prices: By observing previous auction prices for coins with a similar condition (70), we can see that they have reached hammer prices of up to 240 euros in recent auctions. For example, in the auction on March 17, 2022, the coin with a condition of 70 was sold for 240 euros.

3. Starting Price and Average Hammer Price: The current starting price is 150 euros, and the average hammer price in previous auctions is 164.43 euros. This suggests that the hammer price could be in a similar range or slightly above the starting price.

4. Sales Trends: The coin has been auctioned 15 times, of which 14 have sold, indicating good demand. This can influence the hammer price, as a high sales rate suggests that collectors are interested in this coin.

5. Maximum Price Estimate: Given that the highest hammer price for a coin with a similar condition has been 240 euros, and considering that the starting price is 150 euros, a reasonable maximum purchase price could be in the range of 200 to 240 euros, depending on the competition in the auction.

Conclusion: Based on the information provided, an estimated maximum purchase price for this coin could be approximately 220 euros. This allows for a margin to compete in the auction, taking into account the condition and previous hammer prices.