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 (MBC+), 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 has been approximately 39.94 euros.
- In previous auctions, we have seen hammer prices that varied, but some relevant examples are:
- 120 euros for a coin with a condition of 90.
- 45 euros for a coin with a condition of 80.
- 20 euros for a coin with a condition of 75.
- The trend shows that coins with a condition of 80 have reached hammer prices of up to 45 euros.

3. Starting Price and Average Starting Price:
- The starting price is 25 euros, and the average starting price is 31.6 euros. This suggests that the starting price is reasonable and that there could be competition in the auction.

4. Demand and Supply: The coin has been auctioned 25 times in the past, with a 72% sell-through rate, indicating a consistent interest in this coin.

Based on these factors, an estimated maximum purchase price could be around 45-50 euros, as this price reflects the current condition and the hammer price history for similar coins. However, it is important to keep in mind that the final price may vary depending on competition in the auction and other market factors.