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 70 (VF-), indicating a medium state of preservation. This is important because coins in better condition tend to reach higher prices.

2. Auction History:
- The average hammer price for coins with a similar condition (70) has been approximately 70.03 euros.
- In previous auctions, coins with a condition of 70 have reached hammer prices that varied, but generally, they have sold between 48 and 75 euros.

3. Starting Price and Average Starting Price:
- The current starting price is 45 euros, which is slightly higher than the average starting price of 44.55 euros. This suggests that the seller has expectations of a higher hammer price.

4. Recent Trends: In the most recent auctions, the hammer price for coins with a condition of 70 has been in the range of 70 to 90 euros.

Based on these factors, an estimated maximum purchase price could be around 80-90 euros, considering that interest in the coin may increase at the auction and that the condition is acceptable. However, it is important to keep in mind that the final price will depend on the competition in the auction and the interest of other buyers.