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

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

2. Auction History:
- The average hammer price in previous auctions is 70.18 euros.
- Hammer prices in past auctions varied, with some reaching up to 160 euros in the case of a higher condition (in the 2015 auction).
- The most recent auction (2022) with a condition of 80 had a hammer price of 50 euros, while another with a condition of 95 reached 140 euros.

3. Starting Prices and Hammer Prices:
- The current starting price is 15 euros, which is quite low compared to previous hammer prices.
- The average starting price in past auctions is 47.25 euros, suggesting that the coin has a higher market value.

4. Price Trends:
- Since the coin has been auctioned 13 times and has had a high sales percentage (12 out of 13), this indicates a consistent interest in this coin.

Based on these factors, an estimated maximum purchase price could be in the range of 80 to 120 euros, considering that the current condition is 75 and there are precedents of higher hammer prices in better conditions. A price of 100 euros could be a reasonable target, given the auction history and interest in the coin.