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

1. Current Condition: The coin has a condition of 70 (VF-), which indicates that it is in relatively good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Previous Prices: By looking at previous auction prices for coins with similar conditions, we can see that:
- In 2020, a coin with a condition of 75 was auctioned for 80 euros.
- In 2019, another coin with a condition of 75 was also auctioned for 80 euros.
- In 2022, a coin with a condition of 80 was auctioned for 110 euros.

3. Average Auction Price: The average auction price for this coin is 55.23 euros, which gives us an idea of the general market value.

4. Recent Trends: The coin has had a starting price of 30 euros in the current auction, which is a reasonable price, but considering that there have been higher auctions in the past, it is possible that interest in this coin could lead to a higher auction price.

5. Estimation Based on Historical Data: Given that the condition is 70 and considering previous auction prices, an auction price in the range of 60 to 80 euros seems reasonable. However, since interest may vary and there are two upcoming auctions, we might estimate a more conservative maximum purchase price.

Estimated Maximum Purchase Price: Based on all these factors, an estimated maximum purchase price could be 70 euros. This aligns with previous auction prices for similar conditions and allows for some margin for competition in the auction.