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

1. Current Condition: The coin has a condition of 75 (MBC), which indicates that it is in fairly good shape, but not among the best qualities (FDC).

2. Auction History:
- The average hammer price for similar coins has been 534.64 euros.
- In the past, coins with a similar condition (75) have sold for varying prices, with some examples being:
- 595.61 euros (2012)
- 440 euros (2013)
- 425 euros (2015)
- 400 euros (2019)
- There are also examples of coins with higher conditions (90) that have sold for significantly higher prices, such as 1100 euros.

3. Starting Price: The starting price is 100 euros, which indicates that the auctioneer expects interest in the coin.

4. Market Trends: Since the coin has been auctioned 97 times and has had a good sales percentage (77 out of 97), this suggests that there is an active market for this coin.

Based on these factors, an estimated maximum purchase price could be in the range of 500 to 700 euros, considering that the condition is 75 and the average hammer price is 534.64 euros. A price of 600 euros could be a reasonable target, as it aligns with the historical hammer prices for coins in similar conditions.