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, but not the best possible condition.

2. Auction History:
- The average hammer price in previous auctions is 27 euros.
- In recent auctions, hammer prices have varied depending on the condition. For example, in 2019, a coin with a similar condition sold for 110 euros, but that is an exceptional case.
- In 2021, a coin with the same condition (75) was hammered at 50 euros.

3. Starting Price and Average Starting Price: The current starting price is 12 euros, and the average starting price in the past is 17.62 euros. This suggests that interest in the coin may be increasing.

4. Sales Trends: Out of the 14 times it has been auctioned, it has sold 9 times, indicating a good level of interest and demand.

5. Proximity of New Auctions: There are 2 auctions scheduled in the coming days, which could influence demand and price.

Taking all these factors into account, an estimated maximum purchase price for this coin could be in the range of 40 to 50 euros, as this price reflects its condition and historical interest in previous auctions. However, if competition is high at the auction, it might be reasonable to consider a bit more, up to 60 euros, but that will depend on the dynamics at the time of the auction.