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

1. Current Condition: The coin has a condition rating 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. Auction History:
- The average hammer price for similar coins in the past is €1289.14.
- The coin has been auctioned 24 times, of which it has sold 22 times, indicating good demand.
- Previous hammer prices for coins with similar conditions (80) have ranged between €1000 and €1500, with some exceptional cases reaching up to €4400 in extraordinary conditions.

3. Starting Price and Estimates:
- The current starting price is €1500, which is slightly higher than the previous average hammer price.
- The estimated price for this auction is €1500, suggesting that sellers have high expectations.

4. Recent Trends: In the most recent auctions, hammer prices have been on the rise, which could indicate growing interest in this coin.

Based on these factors, an estimated maximum purchase price could be around €1600-€1800, considering that the buyer might be willing to pay a bit more for the good condition and historical demand. However, it is important to keep in mind that the final price will depend on the competition in the auction and the willingness of other bidders.