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

1. Current Condition: The coin has a condition rating of 85 (EF-), indicating that it is in fairly good shape, but not the best possible condition (UNC).

2. Starting Price: The starting price is 60 euros, which can be a good starting point for the auction.

3. Sales History:
- The average hammer price in previous auctions is 300.19 euros, suggesting that, in general, coins of this reference tend to sell for significantly higher prices than their starting price.
- The coin has been auctioned 42 times, of which it has sold 35 times, indicating good demand.

4. Previous Prices:
- In previous auctions, hammer prices have varied considerably, ranging from 44 euros to 1752.31 euros, depending on the condition and other factors.
- The last auction with a similar condition (85) had a hammer price of 90 euros.

5. Market Trends: Given that the average hammer price is quite high compared to the starting price, and considering that the condition of the coin is good, it is reasonable to assume that interest in this coin could lead to a hammer price above the average price.

Based on these factors, an estimated maximum purchase price could be in the range of 250 to 350 euros, considering that the average hammer price is 300.19 euros and that the condition of the coin is quite good.

Therefore, a reasonable maximum purchase price could be 350 euros.