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 relatively good shape. This suggests that its value should be above that of coins with lower conditions.

2. Starting Price and Previous Prices: The current starting price is 125 euros, and the average hammer price in previous auctions is 355.29 euros. This indicates that, generally, coins of this reference tend to sell for significantly higher prices than their starting price.

3. Sales History: The coin has been auctioned 104 times, of which 95 have resulted in sales. This suggests that there is consistent interest in this coin, which may increase its value at auction.

4. Previous Hammer Prices: By 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 reached 220 euros (for example, in the auction on 2019-05-23).

5. Recent Trends: In the most recent auctions, such as the one on 2023-03-16, the coin reached a hammer price of 1700 euros with a condition of 95, indicating that there is potential for high prices for good quality coins.

Based on these factors, an estimated maximum purchase price for the coin in question could be in the range of 300 to 400 euros, considering that the average hammer price is 355.29 euros and that the condition of 80 should allow for a price higher than the current starting price of 125 euros.

Therefore, a reasonable maximum purchase price could be 350 euros.