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 80 (MS+), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction History:
- In the past, the coin has been auctioned 3 times, of which it has sold 2 times. This suggests that there is interest in the coin, which may increase its value.
- Previous hammer prices are 320 (with a condition of 70) and 500 (with a condition of 95). This indicates that the price can vary significantly depending on the condition.

3. Starting Price and Average Hammer Price:
- The current starting price is 325 euros, and the average hammer price in the past has been 410 euros. This suggests that the hammer price could be in a similar range or slightly above the starting price.

4. Price Trends:
- The average starting price in the past has been 337.5 euros, indicating that the current starting price is reasonable and could attract bidders.

5. Proximity of the Auction: The coin will be auctioned in the coming days, which may generate an increase in demand and, therefore, in price.

Taking all these factors into account, an estimated maximum purchase price could be in the range of 450 to 500 euros, given that the condition is good and there is a history of hammer prices that supports this estimate. However, it is important to consider that bidder interest in the auction may influence the final price.