To estimate a maximum purchase price for the coin with a grade of 70 (MBC-), we can analyze historical data and price trends.

1. Historical Data:
- The coin has been auctioned 65 times, of which it has sold 52 times.
- The average hammer price for this coin is 94.47 euros.
- In previous auctions with a grade of 70, hammer prices have varied, but some examples can be observed:
- 2020-09-17: 15 euros
- 2020-02-12: 20 euros
- 2019-12-10: 6 euros
- 2019-10-15: 10 euros
- 2023-01-31: 25 euros

2. Price Trends:
- Hammer prices for coins with a grade of 70 have shown a range from 6 euros to 25 euros in the most recent auctions.
- However, the average hammer price (94.47 euros) suggests that there is a higher selling potential, especially considering that a grade of 70 is relatively good.

3. Estimation:
- Given that the grade is 70 and considering the average hammer price and previous hammer prices, an estimated maximum purchase price could be set in a higher range than the lowest observed prices, but not as high as the overall average.
- A reasonable maximum price could be 30 to 40 euros, taking into account that this is a price that has been reached in recent auctions and reflects good preservation.

Therefore, the estimated maximum purchase price for this coin would be 30-40 euros.