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

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

2. Starting Price and Previous Prices: The current starting price is 200 euros. In previous auctions, the average hammer price has been 451.14 euros, suggesting that buyers are willing to pay significantly more than the starting price.

3. Price Trends: By observing the hammer prices of previous auctions for coins with a similar condition (85), we can see that they have reached hammer prices that vary but generally tend to be higher than the current starting price.

4. Recent Hammer Prices: In the most recent auctions, the hammer prices for coins with similar conditions have been 650 euros and 480 euros, indicating that there is interest and a willingness to pay higher prices.

5. Estimation Based on Historical Data: Given that the average hammer price is 451.14 euros and considering that the condition of this coin is good, an estimated maximum purchase price could be in the range of 600 to 700 euros, taking into account the trend of hammer prices in recent auctions.

Conclusion: An estimated maximum purchase price for this coin could be approximately 650 euros. This value reflects both the condition of the coin and the price trends observed in previous auctions.