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 rating of 80 (MBC+). This is an important factor, as coins in better condition tend to reach higher prices.

2. Auction History: The coin has been auctioned 11 times and has sold on all occasions. This indicates a consistent demand.

3. Previous Hammer Prices: Previous hammer prices are relevant for establishing a price range. The hammer prices have varied, but the highest was 1600 euros in a recent auction (2024) with a condition of 70, suggesting that coins in similar conditions can reach high prices.

4. Average Hammer Price: The average hammer price is 1086.36 euros, providing a solid benchmark.

5. Price Trends: Observing previous hammer prices, it seems there is a trend for coins in conditions similar to the current one (80) to sell in a range of 900 to 1400 euros.

Given all this, an estimated maximum purchase price could be around 1300 euros, considering that the condition is good and that the auction history shows prices can reach higher figures in similar conditions. However, it is important to keep in mind that the final price may depend on competition in the auction and demand at that specific moment.