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

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 132.29 euros.
- Hammer prices in past auctions varied, with a maximum price of 220 euros in 2011 and other significant prices in subsequent years.

3. Starting Price: The current starting price is 40 euros, which is relatively low compared to the average hammer price.

4. Sales Trends: Of the 11 times it has been auctioned, it has sold on 8 occasions, indicating a consistent interest in the coin.

5. Comparison with Previous Prices:
- In recent auctions, hammer prices have ranged between 50 and 140 euros, with a starting price of 100 euros in 2019 that reached a hammer price of 140 euros.

Given all this, an estimated maximum purchase price could be set in a range between 140 and 180 euros, considering that the condition is good and that interest in the coin appears to be solid. A price of 160 euros could be a reasonable target, as it falls in the middle of this range and reflects both the price history and the current condition.