To estimate a maximum purchase price for the coin in question, we can analyze the provided data, especially the current grade of the coin (75, MS) and the hammer prices from previous auctions.

1. Grade: The coin has a grade of 75 (MS), indicating that it is in fairly good condition, but not of the highest quality (PR).

2. Previous hammer prices: By observing the hammer prices of coins with similar grades:
- In previous auctions, hammer prices for coins with grades ranging from 70 to 90 have varied significantly. For example:
- A coin with a grade of 70 was sold for 10 euros.
- A coin with a grade of 75 was sold for 10 euros.
- A coin with a grade of 90 was sold for 75 euros.
- A coin with a grade of 85 was sold for 220 euros.

3. Average hammer price: The average hammer price for this coin is 49.17 euros, which can serve as a reference.

4. Price trends: Given that the coin has a grade of 75, it is reasonable to assume that it could reach a hammer price in the range of 30 to 70 euros, based on previous hammer prices and the general trend.

5. Final estimate: Taking all these factors into account, an estimated maximum purchase price for this coin could be around 60 euros. This is based on the fact that there have been previous auctions with higher hammer prices for similar grades, but also considering that the market can vary and that the grade is not the highest.

Therefore, a reasonable maximum purchase price would be 60 euros.