To estimate a maximum purchase price for the coin in question, we will take several factors into account:

1. Current Condition: The coin has a condition of 70 (VF-). This indicates that it is in an acceptable state, but not of high quality.

2. Auction History:
- The average hammer price for similar coins has been 119.88 euros.
- In the past, coins with a similar condition (70) have had hammer prices that vary, but we can observe that the highest hammer price for a coin with a condition of 70 was 31 euros (on 2020-10-20).
- There are also examples of coins with higher conditions (such as 80 or 85) that have sold for significantly higher prices, suggesting that condition is an important factor in pricing.

3. Starting Price: The starting price is 15 euros, indicating that the seller expects a low minimum price.

4. Recent Trends: In recent auctions, hammer prices for coins of similar condition have ranged between 15 and 31 euros, with an average hammer price tending to be higher for coins in better condition.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 30 to 50 euros. This is based on the auction price history for coins of similar condition and the potential interest from collectors. However, since the condition is not high, it is wise not to exceed 50 euros in the bid.