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 85 (ebc-), which indicates that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction History:
- The average hammer price in previous auctions is 104.02 euros, suggesting that, in general, coins of this reference tend to sell above their starting price.
- In the most recent auction (2022), a coin with a similar condition (85) sold for 68 euros, which may be an indicator of its current market value.

3. Starting Price: The starting price is 70 euros, which is a reasonable starting point for the auction.

4. Sales Trends: Out of the 10 times it has been auctioned, it has sold 4 times, indicating a moderate interest in this coin.

5. Comparison with Previous Prices: In previous auctions, hammer prices have varied, but there are examples of sales above 100 euros, especially for coins in better condition.

Taking all these factors into account, an estimated maximum purchase price could be around 100-120 euros. This is based on the hammer price history and the current condition of the coin. However, it is important to consider that the final price may be affected by competition in the auction and demand at the time of sale.