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

1. Current Condition: The coin has a condition rating of 70 (VF-). This indicates that it is in an acceptable state, but not of high quality. In the coin market, condition is a crucial factor that affects price.

2. Auction History:
- The average hammer price for similar coins in the past has been 4299.47 euros.
- The coin has been auctioned 43 times, of which 39 have been successful sales. This indicates good demand in the market.
- Previous hammer prices for coins with similar conditions (70) have varied, but there are examples of auctions that have reached up to 3600 euros in recent sales.

3. Starting Price: The current starting price is 750 euros, which is relatively low compared to the average hammer price.

4. Price Trends: Observing the hammer prices of coins with similar conditions, the range seems to be between 1200 and 3600 euros, depending on demand and other market factors.

Based on these points, an estimated maximum purchase price for this coin could be in the range of 3000 to 3600 euros. This range takes into account the current condition, price history, and market trends. However, it is important to note that the final price may vary depending on competition in the auction and other external factors.