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

1. Current Condition: The coin has a condition of 75 (MBC), which indicates that it is in fairly good shape, although it is not the best possible condition.

2. Auction History:
- The average hammer price in previous auctions is 160.9 euros.
- The coin has been auctioned 12 times, of which it has sold 11 times, indicating good demand.
- Previous hammer prices varied, but there are examples of auctions reaching up to 850 euros (in a 2019 auction with a condition of 95).

3. Starting Prices and Estimates:
- The current starting price is 40 euros, and the average starting price in the past has been 60 euros.
- The estimated price for this auction is 70 euros.

4. Price Trends:
- In previous auctions, hammer prices have fluctuated, but there is a pattern that coins in similar conditions have reached hammer prices around 75-150 euros.

Based on this data, an estimated maximum purchase price could be in the range of 150 to 200 euros, considering that the condition is good and that the hammer price history suggests potential for higher prices. However, since the coin has a condition of 75 and is not the highest, a prudent maximum purchase price could be approximately 180 euros.