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 rating of 80 (MBC+), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Starting Price and Average Hammer Price: The starting price is 100 euros, and the average hammer price in previous auctions is 113.46 euros. This suggests that, on average, similar coins have reached prices above the starting price.

3. Sales History: The coin has been auctioned 118 times, of which it has sold 103 times. This indicates good demand and a history of successful sales.

4. Previous Prices: Looking at previous hammer prices for coins with a similar condition (80), we can see that they have reached hammer prices that vary, but some have exceeded 150 euros in recent auctions.

5. Recent Trends: In the most recent auctions, hammer prices for coins of similar condition have ranged from 110 to 140 euros, suggesting that interest and value for these coins are on the rise.

Based on these factors, an estimated maximum purchase price for this coin could be between 140 and 160 euros, considering that the condition is good and there is a history of hammer prices that supports this estimate.

Therefore, a reasonable maximum purchase price could be 150 euros.