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 75 (MBC), which indicates 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 135.77 euros.
- The coin has been auctioned 14 times, of which it has sold 13 times, indicating good demand.
- Previous hammer prices for coins with similar conditions (70-80) have varied, but there are examples of auctions reaching up to 150 euros.

3. Starting Price and Average Starting Price:
- The current starting price is 25 euros, which is quite low compared to the average starting price of 94.62 euros. This suggests that there is potential for a significant increase in the hammer price.

4. Price Trends:
- In previous auctions, hammer prices have shown a trend of being significantly higher than starting prices, especially for coins in good condition.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 150 to 180 euros. This is based on the auction price history and the current condition of the coin.