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

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

2. Current Listing Price and Previous Prices: The current listing price is 1300 euros, which is above the average listing price of 920.83 euros. However, the average hammer price is 1089.78 euros, suggesting that similar coins have been selling for below the current listing price.

3. Sales History: In the past, the coin has had hammer prices that varied, but there are several examples where coins with similar conditions (80) have sold for prices around 1200 euros. For instance, in 2020, a coin with a condition of 80 sold for 1200 euros.

4. Recent Trends: In the most recent auctions, hammer prices have been in the range of 1400 to 1800 euros for coins of similar condition, indicating a possible increase in demand.

Taking these factors into account, an estimated maximum purchase price could be around 1400-1500 euros. This is based on the sales history, current condition, and price trends in recent auctions. However, since the listing price is 1300 euros, it is likely that buyers would be willing to pay a little more, but not much beyond this range to avoid the risk of overpaying.