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 75 (MBC). This is an important factor, as coins in better condition tend to reach higher prices.

2. Auction History:
- The average hammer price for similar coins in the past is 116.27 euros.
- The condition of the coins that have been sold in the past varies, but there are examples of coins with similar conditions (75) that have sold for prices ranging from 25 to 80 euros, and some in better condition (85-95) that have reached much higher prices (up to 650 euros).

3. Starting Price and Average Starting Price:
- The current starting price is 15 euros, which is quite low compared to the average hammer price.
- The average starting price for similar coins is 80.21 euros.

4. Recent Trends: In recent auctions, coins with similar conditions have had hammer prices that vary, but there is a pattern that coins in MBC condition (75) tend to sell in a range of 30 to 80 euros.

Based on these factors, an estimated maximum purchase price for the coin in question could be in the range of 80 to 120 euros. This is based on the auction price history and the current condition of the coin. However, since the starting price is 15 euros, it could be a good opportunity to acquire it at a lower price if the competition in the auction is not high.