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

1. Current Condition: The coin has a condition of 70 (MBC-). 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 (70 and 75), we can see that:
- In past auctions, coins with a condition of 70 have reached hammer prices ranging from 41 to 95 euros.
- Coins with a condition of 75 have reached hammer prices of up to 161 euros.

3. Average Hammer Price: The average hammer price for this coin is 113.17 euros, indicating that, in general, buyers are willing to pay more than the starting price.

4. Recent Trends: In the most recent auctions, the hammer price has been in a range of 130 to 170 euros for conditions of 75 and 80, suggesting an upward trend in prices.

5. Starting Price: The starting price is 30 euros, which is relatively low compared to previous hammer prices.

Based on these factors, an estimated maximum purchase price for the coin with a condition of 70 could be in the range of 90 to 120 euros. This is because, although the condition is not the highest, the interest in the coin and previous hammer prices suggest it could reach a higher price than average.

Therefore, a reasonable estimated maximum purchase price could be 100 euros.

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

1. Coin Condition: The coin has a condition rating of 80 (MBC+), indicating that it is in quite good shape.

2. Auction History:
- It has been auctioned 14 times in the past, of which it has sold 11 times.
- The average starting price is 23.21 euros, and the average hammer price is 28.64 euros.
- In previous auctions, hammer prices for coins with similar condition (80) have varied, but there was a recent hammer price of 18 euros in 2021 and a hammer price of 80 euros in 2019.

3. Price Trends:
- Hammer prices for coins with a condition rating of 70 to 80 have ranged between 15 and 80 euros, suggesting a wide range depending on demand and supply at the time of the auction.

4. Current Starting Price: The starting price is 18 euros, which is relatively low compared to the average hammer price.

Based on this data, an estimated maximum purchase price could be set in a range between 30 and 50 euros, considering that the condition is good and the average hammer price is 28.64 euros.

Therefore, a reasonable maximum purchase price could be 40 euros. This allows for some margin for competition in the auction, given that the starting price is low and the condition is good.