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

1. Coin Condition: The coin has a condition rating of 80 (MBC+), indicating that it is in relatively good shape. This suggests that its value should be above that of coins in worse condition.

2. Previous Auction Prices: By observing the hammer prices of coins with a similar condition (80), we can see that they have reached hammer prices that vary, but generally, the hammer prices for coins in similar conditions have been in the range of 25 to 170 euros, depending on demand and other factors.

3. Average Hammer Price: The average hammer price for this coin is 128.83 euros, which provides a good reference for the expected value.

4. Starting Price and Recent Auction Prices: The current starting price is 30 euros, which is quite low compared to the average hammer price. This suggests that there is potential for the hammer price to be significantly higher.

5. Auction Trends: Since it has been auctioned 266 times and sold 230 times, there is good demand for this coin, which may increase its price at auction.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 150 to 200 euros, considering that the average hammer price is 128.83 euros and that the condition is good. This also takes into account the possibility that demand in the current auction may be high, which could push the price towards the upper end of this range.