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 in previous auctions is 72.5 euros.
- The coin has had hammer prices that vary significantly, with some reaching up to 280 euros in the case of a condition rating of 90.
- The price trend appears to be increasing, especially for coins in good condition.

3. Starting Price and Average Starting Price:
- The current starting price is 15 euros, which is quite low compared to the average starting price of 38.85 euros.
- This suggests that there is potential for the hammer price to be considerably higher.

4. Comparison with Previous Prices:
- In previous auctions, coins with similar conditions have reached hammer prices ranging from 35 to 280 euros, depending on demand and other factors.

Given all this, an estimated maximum purchase price for this coin, considering its condition and price history, could be in the range of 80 to 120 euros. This range reflects both the potential of the coin in the current market and its condition.