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

1. Coin Condition: The coin has a condition rating of 70 (MBC-), indicating that it is in acceptable condition, but not among the best qualities.

2. Average Hammer Price: The average hammer price for similar coins in the past is 73.87 euros. This gives us a good reference for what buyers are willing to pay.

3. Auction History: The coin has been auctioned 96 times, of which it has sold 86 times. This indicates good demand and a history of successful sales.

4. Previous Prices: Looking at previous hammer prices for coins with a similar condition (70), prices have varied, but many have been in the range of 55 to 90 euros.

5. Starting Price: The starting price is 40 euros, which is relatively low compared to the average hammer price.

Considering all these factors, an estimated maximum purchase price could be in the range of 80 to 90 euros. This is based on the average hammer price and the price history for coins of similar condition.

Therefore, a reasonable estimated maximum purchase price would be 85 euros.