To estimate a maximum purchase price for the coin in question, we will consider several factors:

1. Current Condition: The coin has a condition rating of 75 (MBC), indicating 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 for similar coins has been 76.3 euros.
- In previous auctions, hammer prices have varied, but there are examples of coins with similar conditions that have sold for prices ranging from 40 to 190 euros, depending on the condition and demand.

3. Starting Price and Estimated Price:
- The current starting price is 40 euros, which is relatively low compared to the average hammer price.
- The estimated hammer price for this coin could be in the range of 70 to 90 euros, based on auction history and condition.

4. Sales Trends: The coin has been sold in 11 out of the last 12 auctions, indicating good demand.

Taking all these factors into account, an estimated maximum purchase price for this coin could be between 80 and 100 euros. This is based on the current condition, hammer price history, and sales trends. However, the final price will depend on the competition in the auction and the specific demand at that time.