To estimate a maximum purchase price for the coin in question, we can consider several factors based on the provided data:

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 in the past is 33.24 euros.
- The last auction for this coin had a starting price of 9 euros, suggesting that interest may be moderate.
- In previous auctions, coins with a similar condition (70) have had hammer prices that vary, but some examples are:
- 10 euros (2020-12-15)
- 12 euros (2022-09-20)
- 22 euros (2017-09-21)

3. Price Trends:
- The average starting price is 24.49 euros, indicating that, in general, coins of this reference tend to have a higher value than the current starting price.

4. Demand and Supply:
- It has been auctioned 78 times and sold 61 times, indicating considerable interest in this coin.

Based on these factors, an estimated maximum purchase price could be in the range of 25 to 35 euros, considering that the average hammer price is 33.24 euros and that the condition is 70. This suggests that, although the coin is not of the best quality, it still holds significant value in the market.

Therefore, a reasonable maximum purchase price could be 30 euros.