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

1. Condition: The coin has a condition rating of 85 (ebc-), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction history:
- The average hammer price for similar coins has been 64.43 euros.
- In previous auctions, coins with a similar condition (85) have reached hammer prices that vary, but some examples are:
- 2019-07-03: Hammer price of 70 euros.
- 2018-10-16: Hammer price of 125 euros.
- 2022-07-07: Hammer price of 110 euros.

3. Starting price and average starting price: The current starting price is 40 euros, and the average starting price is 47.65 euros. This suggests that the market is willing to pay more than the starting price.

4. Recent trends: In the most recent auctions, the hammer price has been increasing, which may indicate growing interest in this coin.

Taking all these factors into account, an estimated maximum purchase price could be in the range of 80 to 120 euros, considering that the condition is good and there is a history of hammer prices that supports this estimate.

Therefore, a reasonable maximum purchase price could be 100 euros.