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 70 (VF-), indicating that it is in acceptable condition, but not among the best. This may influence the price, as coins in better condition tend to fetch higher prices.

2. Auction History:
- The average hammer price in previous auctions is 69.47 euros.
- The coin has been auctioned 19 times, of which it has sold 15 times. This indicates good demand.
- In previous auctions, hammer prices have varied, but there are examples of hammer prices exceeding 80 euros, especially for coins in better condition.

3. Starting Price and Average Starting Price:
- The current starting price is 25 euros, which is relatively low compared to the average starting price of 47.44 euros.

4. Price Trends:
- In recent auctions, the hammer price has reached up to 160 euros for coins in better condition. However, for a coin with a condition rating of 70, it is reasonable to expect a lower price.

Taking all these factors into account, an estimated maximum purchase price for this coin could be between 70 and 90 euros. This is based on the auction price history and the current condition of the coin. A price of 80 euros could be a reasonable target, given that it is in acceptable condition and there is demand in the market.