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

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

2. Auction History:
- The average hammer price in previous auctions is 208.64 euros.
- The coin has been auctioned 12 times, of which it has sold 11 times, indicating good demand.
- Previous hammer prices for coins with a similar condition (80) have varied, but there are examples of auctions reaching up to 220 euros.

3. Starting and Hammer Prices:
- The current starting price is 175 euros, which is lower than the historical average hammer price.
- In previous auctions, starting prices have ranged from 110 to 300 euros, with hammer prices reaching up to 360 euros in the past.

4. Recent Trends: In the most recent auctions, hammer prices have shown a trend of stabilizing or increasing, especially for coins in good condition.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 220 to 250 euros, considering that the condition is good and that the hammer price history supports this estimate. Therefore, a reasonable maximum purchase price could be 240 euros.