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

1. Starting Price: 1200 euros.
2. Condition: The coin has a condition rating of 80 (MBC+), indicating that it is in quite good shape.
3. Auction History:
- It has been auctioned 5 times in the past, of which it has sold 4 times.
- The average hammer price in previous auctions is 1212.5 euros.
- In past auctions, the hammer prices have varied, with the highest being 1500 euros in 2022, while the lowest was 850 euros in 2023.

4. Price Trends:
- The average starting price in previous auctions is 1062.5 euros, suggesting that the current starting price of 1200 euros is slightly higher than the historical average.
- However, the highest hammer price (1500 euros) indicates that there is potential for selling at higher prices, especially if the condition is good.

Given that the coin's condition is rated at 80 (MBC+), which is quite good, and considering the price history, an estimated maximum purchase price could be positioned within a range between the starting price and the highest hammer price.

Estimated Maximum Purchase Price: It may be reasonable to consider a maximum purchase price of around 1400 euros, as this would be below the highest hammer price and reflects potential interest in the coin given its good condition.