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

1. Current Condition: The coin has a condition rating of 80 (MS+), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Current Listing Price and Previous Prices: The current listing price is 175 euros, and the average hammer price in previous auctions is 184.54 euros. This suggests that the hammer price tends to be close to the listing price, which is a good indicator.

3. Auction History: In the auction history, we can observe hammer prices that vary, but there are several examples of coins with similar conditions that have sold for prices exceeding 200 euros. For instance, in recent auctions, coins with a condition of 80 have reached hammer prices of 230 euros and 290 euros.

4. Market Trends: Given that the coin has been auctioned 40 times and has a history of successful sales, this indicates consistent demand. Additionally, the average hammer price of 184.54 euros suggests that buyers are willing to pay a bit more than the listing price.

Based on these factors, an estimated maximum purchase price could be between 220 and 250 euros. This is based on the hammer price history for coins of similar condition and the trend of prices in recent auctions.

Therefore, a reasonable maximum purchase price could be 250 euros.