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

1. Current Condition: The coin has a condition of 80 (MBC+). This is an important factor, as coins in better condition tend to reach higher prices.

2. Historical Prices: By observing previous auction prices, we can see that the coin has reached auction prices that vary considerably. For example:
- In 2012, it was auctioned for 927.36 euros with a condition of 90.
- In 2014, it was auctioned for 3082.03 euros with a condition of 90.
- In 2016, it was auctioned for 2026.59 euros with a condition of 107.
- In 2022, it was auctioned for 420 euros with a condition of 85.

3. Average Auction Price: The average auction price for this coin is 965.79 euros, which gives us an idea of the general value it moves in.

4. Current Starting Price: The starting price is 150 euros, which may attract more bidders, but the final auction price could be significantly higher.

5. Auction Trends: Since the coin has been auctioned 8 times and all have been sold, this indicates a consistent interest in the coin.

Based on these factors, an estimated maximum purchase price could be situated in a range between the average auction price and the higher prices reached in previous auctions. Given that the current condition is 80, which is lower than the conditions of 90 and 107 that reached higher prices, it is reasonable to adjust the price downward.

Estimated Maximum Purchase Price: It could be reasonable to estimate a maximum purchase price around 800-1000 euros, considering the condition and historical prices. This would allow a competitive bidder to have a good opportunity to acquire the coin without exceeding the market value demonstrated in previous auctions.