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 shape, but not among the best qualities. 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 87.17 euros.
- The coin has been auctioned 15 times, of which it has sold 12 times, indicating good demand.
- Previous hammer prices for coins with similar conditions (70) have ranged between 75 and 160 euros, depending on the auction and other factors.

3. Starting Price and Estimated Price:
- The current starting price is 60 euros, which is consistent with the average starting price of 60.71 euros.
- The estimated hammer price in previous auctions has been up to 200 euros, although this may be an exceptional case.

4. Recent Trends: In the most recent auctions, the hammer price has been around 100 euros for coins with similar conditions.

Based on these factors, an estimated maximum purchase price for this coin could be between 90 and 120 euros, considering that the condition is 70 and that the price history shows it has reached higher prices in the past.

Therefore, a reasonable maximum purchase price could be 100 euros.