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 rating of 70 (VF-), indicating that it is in relatively good shape. This can positively influence its value.

2. Previous Auction Prices:
- The average hammer price from previous auctions is 141.2 euros.
- The current starting price is 150 euros, which is slightly higher than the previous average hammer price.
- In previous auctions, the hammer prices have varied, but the highest was 190 euros.

3. Sales Trends:
- It has sold in 6 out of the 7 times it has been auctioned, indicating good demand.
- The coin will be auctioned in the coming days, which may increase interest and competition among bidders.

4. Estimated Price: The estimated price for this auction is 200 euros, suggesting that there are expectations for the coin to reach a higher value.

5. Comparison with Previous Prices:
- In the most recent auction (2023), the coin was offered at 140 euros and was expected to reach 200 euros, indicating that the market is willing to pay more for coins in good condition.

Taking all these factors into account, a reasonable estimated maximum purchase price could be around 180-200 euros. This is based on the current condition, historical demand, and the estimated price for the auction. However, since the starting price is 150 euros, bidders may be willing to pay a bit more, especially if there is interest in the coin.

Therefore, a reasonable maximum purchase price could be 200 euros.