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

1. Current Condition: The coin has a condition rating of 85 (MBC+/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 in previous auctions is 83.27 euros.
- The coin has been auctioned 40 times, of which it has sold 35 times, indicating good demand.
- In recent auctions, hammer prices have reached up to 290 euros (in 2018) and 220 euros (in 2022), although these prices may correspond to higher conditions.

3. Starting Price and Average Starting Price:
- The current starting price is 75 euros, and the average starting price in the past has been 53.97 euros. This suggests that the current starting price is reasonable and could attract bidders.

4. Recent Trends: In the most recent auctions, hammer prices have varied, but there are examples of hammer prices exceeding 100 euros, indicating potential for a higher hammer price.

Based on these factors, an estimated maximum purchase price could be in the range of 100 to 130 euros, considering that the condition is good and there is a history of hammer prices supporting this estimate. However, since the market can be volatile and depends on demand at the time of the auction, it is advisable to be prepared to adjust the bid according to the competition.