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 75 (MBC), indicating that it is in fairly good shape, but not the best possible condition.

2. Previous Auction Prices: By looking at previous auction prices for coins with similar conditions (around 70-80), we can see that auction prices have varied. For example:
- In recent auctions, coins with a condition of 70 have reached auction prices of up to 270 euros.
- Coins with a condition of 80 have reached auction prices of up to 360 euros.

3. Average Auction Price: The average auction price for this coin is 183.72 euros, giving us an idea of what buyers are willing to pay on average.

4. Starting Price: The starting price is 180 euros, indicating that the seller expects a reasonable price based on the market.

5. Auction Trends: The coin has been auctioned 99 times, with a high sales percentage (92 out of 99), suggesting that there is consistent interest in this coin.

Based on these factors, an estimated maximum purchase price could be in the range of 250 to 300 euros, considering that the condition is good and there are precedents of higher auction prices for similar conditions.

Therefore, a reasonable maximum purchase price could be approximately 280 euros.