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

1. Current Condition: The coin has a condition rating of 85 (MBC+/EBC-), indicating that it is in quite good shape. This generally translates to a higher price compared to coins in lower condition.

2. Previous Auction Prices:
- The average hammer price for similar coins in the past is 330.32 euros.
- Previous hammer prices for this same coin varied, but there was a hammer price of 579.03 euros in 2015 for a coin with a condition of 75, suggesting that the price could be significantly higher for a coin in better condition.

3. Current Starting Price: The starting price is 125 euros, which is quite low compared to the average hammer price.

4. Sales Trends: Out of the 7 times it has been auctioned, it has sold 4 times, indicating interest in the coin, although it did not sell 3 times, which may be a factor to consider.

5. Proximity of the Auction: There is an auction scheduled in the coming days, which may influence demand and price.

Based on these factors, an estimated maximum purchase price could be in the range of 300 to 400 euros, considering that the condition is good and the average hammer price is 330.32 euros. However, given the interest in the coin and the relatively low starting price, a reasonable maximum purchase price could be approximately 350 euros.