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 is a good condition, but not the best. This suggests that the price should not be as high as that of coins in superior conditions.

2. Auction History:
- The average hammer price for similar coins in similar conditions is 86.78 euros.
- In previous auctions, the coin has reached hammer prices that varied, but generally, hammer prices for coins with a condition of 70 have been in the range of 46 to 130 euros.

3. Starting Price and Previous Prices:
- The current starting price is 50 euros, which is relatively low compared to previous hammer prices.
- The average starting price in the past has been 56.74 euros, indicating that the current starting price is competitive.

4. Price Trends:
- In the most recent auctions, hammer prices have been increasing, which could indicate a rising trend in interest for this coin.

Taking all these factors into account, an estimated maximum purchase price could be around 90-110 euros. This is based on the average hammer price and the price history of coins in similar conditions. However, since the starting price is 50 euros, it could be a good buying opportunity if it can be acquired below this range.