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

1. Current Condition: The coin has a condition of 80 (MBC+), which indicates that it is in fairly good shape, but not of the highest quality (FDC).

2. Historical Prices: By looking at previous auction prices for coins with similar conditions (80 and 85), we can see that auction prices have varied. For example:
- In previous auctions, coins with a condition of 80 have reached hammer prices of up to 190 euros.
- Coins with a condition of 85 have reached hammer prices of up to 240 euros.

3. Starting Price and Average Hammer Price: The current starting price is 175 euros, and the average hammer price in the past has been 151.18 euros. This suggests that the starting price is relatively high compared to the average hammer price.

4. Recent Trends: In the most recent auctions, hammer prices for coins with similar conditions have been in the range of 180 to 225 euros.

Based on these factors, an estimated maximum purchase price could be in the range of 200 to 225 euros. This is because, although the starting price is 175 euros, the trend of hammer prices for coins of similar condition suggests that there may be enough interest to reach a higher price.

Therefore, an estimated maximum purchase price for this coin could be 225 euros.