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-). This is an important factor, as coins in better condition tend to reach higher prices.

2. Auction History:
- The average hammer price for similar coins in condition 70 has been between 35 and 55 euros in previous auctions.
- In particular, at the 2020 auction, a coin with the same condition (70) was sold for 35 euros.
- In other auctions, hammer prices have varied, but the range seems to be between 30 and 110 euros, depending on the condition and demand.

3. Starting Price and Average Hammer Price:
- The current starting price is 30 euros, and the average hammer price for similar coins is 103.62 euros. This suggests that there is potential for a higher hammer price, but it also depends on the demand at the auction.

4. Recent Trends: In the most recent auction, the hammer price was 70 euros for a coin with the same condition.

Based on these factors, an estimated maximum purchase price could be in the range of 70 to 90 euros, considering that the coin has an acceptable condition and there has been interest in similar coins in the past. However, since the starting price is 30 euros, it is possible that the hammer price may not reach the estimated maximum if demand is not high.

Therefore, a reasonable maximum purchase price could be 80 euros.