To estimate a maximum purchase price for the coin with a grade of 85 (ebc-), we can analyze historical data and price trends.

1. Current coin data:
- Starting price: €30
- Grade: 85 (ebc-)

2. Relevant historical data:
- In previous auctions, coins with a grade of 85 have had hammer prices that varied, but some examples are:
- €50 (2020-12-15)
- €40 (2020-12-15)
- €55 (2020-05-26)
- €45 (2019-03-14)
- €70 (2018-10-17)
- €90 (2018-10-15)

3. Price analysis:
- The average hammer price for coins with a similar grade (85) seems to be in the range of €40 to €70, with some exceptional cases reaching up to €90.
- The average hammer price of the coin in question is €52.34, suggesting that this could be a good reference point.

4. Maximum price estimation:
- Given that the grade is 85 and considering previous hammer prices, a reasonable maximum purchase price could be in the range of €70 to €90.
- However, to be conservative and considering that the starting price is €30, a safer maximum purchase price could be approximately €70.

Therefore, the estimated maximum purchase price for the coin with a grade of 85 (ebc-) would be €70.