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 of 75 (MBC), indicating that it is in an acceptable state, but not of the highest quality.

2. Previous Auction Prices:
- The average hammer price for similar coins has been 571.11 euros, suggesting that there is a market willing to pay significantly higher prices than the starting price.
- In previous auctions, the coin has reached hammer prices that varied, but some examples are:
- 130 euros (2015)
- 260 euros (2014)
- 1500 euros (2014, but with an unspecified condition)
- 400 euros (2021, condition 90)
- 350 euros (2022, condition 85)
- 250 euros (2022, condition 75)
- 1900 euros (2024, condition 95, but this is an exceptional case)

3. Starting Price and Average Starting Price: The current starting price is 125 euros, and the average starting price in the past has been 218.75 euros. This suggests that the current starting price is relatively low compared to the historical average.

4. Market Trends: Given that the coin has been sold on all previous occasions and considering that the average hammer price is high, it is reasonable to assume that there is active interest in this coin.

Based on these factors, an estimated maximum purchase price could be in the range of 300 to 400 euros, considering that the condition is 75 and that interest in the coin appears to be strong. This also takes into account that the highest hammer price in the past for a similar condition was 350 euros.

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