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

1. Condition: The coin has a condition rating of 95 (EF+), indicating that it is in very good shape. This generally increases its value compared to coins with lower conditions.

2. Auction History:
- The average hammer price in previous auctions is 27.64 euros.
- In past auctions, starting and estimated prices have varied, but the highest hammer prices for coins with similar conditions have reached up to 110 euros (in 2020 and 2018).

3. Price Trends:
- The coin has a starting price of 18 euros in the current auction, which is lower than the average starting price of 29 euros in previous auctions.
- The hammer price trend for coins of similar condition suggests that the price could be in the range of 60 to 110 euros, depending on demand in the auction.

4. Number of Auctions: The coin has been auctioned 19 times, with a 63% sell-through rate, indicating consistent interest in the coin.

Based on these factors, an estimated maximum purchase price could be in the range of 60 to 80 euros. This is based on the good condition of the coin and the hammer price history in previous auctions. However, it is important to note that the final price may vary depending on competition in the auction and current demand.