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. Current Starting Price and Previous Prices: The current starting price is 45 euros, and the average hammer price in previous auctions is 101.29 euros. This suggests that the hammer price can be significantly higher than the starting price.

3. Sales History: The coin has been auctioned 177 times, of which it has sold 151 times. This indicates good demand and liquidity in the market.

4. Previous Hammer Prices: Looking at previous hammer prices for coins with a similar condition (80), we can see that they have reached hammer prices of up to 100 euros or more on several occasions.

5. Recent Trends: In the most recent auctions, hammer prices for coins with a condition of 80 have been in the range of 60 to 110 euros.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 100 to 120 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 110 euros.