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

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 with lower conditions.

2. Previous Auction Prices: By looking at the auction prices of coins with a similar condition (80), we can see that they have reached auction prices that vary, but some examples are:
- 55 euros (2020-10-20)
- 50 euros (2020-09-22)
- 60 euros (2022-03-23)
- 135 euros (2022-09-14)

3. Average Auction Price: The average auction price for this coin is 145.61 euros, indicating that, in general, coins of this reference tend to sell for higher prices.

4. Average Starting Price: The average starting price is 64.71 euros, suggesting that sellers are willing to start auctions at relatively low prices compared to the auction prices.

5. Recent Trends: The coin has been auctioned 94 times, of which 83 have been successful sales. This indicates good demand and sustained interest in the coin.

Based on these factors, an estimated maximum purchase price for the coin in question could be in the range of 150 to 200 euros, considering that the condition is good and that the average auction price is significantly higher than the starting price.

Therefore, a reasonable estimated maximum purchase price could be 180 euros.