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 relatively good shape, but not among the best qualities.

2. Historical Prices: By looking at previous auction prices for coins with similar conditions, we can see that auction prices have varied. For example:
- In previous auctions, coins with conditions ranging from 70 to 80 have had hammer prices between 130 and 220 euros.
- The last auction of a coin with a condition of 95 reached a hammer price of 340 euros, indicating that the value can increase significantly with better condition.

3. Starting Price and Average Hammer Price: The current starting price is 200 euros, and the average hammer price in the past has been 170.74 euros. This suggests that the starting price is slightly higher than the previous average hammer price.

4. Market Trends: Since the coin has been auctioned 98 times and has had a high sales percentage (89 out of 98), this indicates a constant interest in this coin, which may influence the price.

5. Condition-Based Estimation: Given that the condition is 75, a reasonable hammer price could be in the range of 180 to 250 euros, considering that the starting price is 200 euros and that interest in the coin may lead to a higher hammer price.

Conclusion: Based on these factors, an estimated maximum purchase price for this coin could be around 250 euros. This allows for some margin for competition in the auction, given the interest in the coin and its condition.