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

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

2. Previous prices: By looking at previous auction prices for coins with a similar condition (85), we can see that they have reached auction prices that vary, but some examples are:
- 76 euros (2022-05-31)
- 121 euros (2021-06-22)
- 80 euros (2022-07-14)
- 240 euros (2022-05-07, although this coin does not have a specified condition)

3. Average auction price: The average auction price for this coin is 109.96 euros, which is also a good indicator of the value that buyers are willing to pay.

4. Starting price and average starting price: The current starting price is 75 euros, and the average starting price is 81.49 euros. This suggests that the starting price is in a reasonable range, but it could be higher given the interest in the coin.

5. Auction trends: The coin has been auctioned 74 times, with an 80% sell-through rate (59 out of 74). This indicates a consistent interest in the coin.

Based on these factors, an estimated maximum purchase price could be in the range of 120 to 150 euros, considering that the condition is good and that the average auction price is above 100 euros. This also takes into account the possibility that some buyers may be willing to pay a bit more for a coin in good condition.

Therefore, an estimated maximum purchase price could be 150 euros.