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

1. Current Condition: The coin has a condition 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: By observing previous hammer prices for coins with similar conditions, we can see that coins in the condition range of 80 to 95 have achieved hammer prices that vary considerably. For example, in previous auctions, coins with a condition of 95 have reached hammer prices of up to 110 euros.

3. Average Hammer Price: The average hammer price for this coin is 50.65 euros, which gives us a good reference for what buyers are willing to pay.

4. Starting Price: The starting price is 25 euros, which is relatively low compared to the average hammer price.

5. Recent Trends: In the most recent auctions, hammer prices have ranged between 35 and 90 euros for similar conditions.

Taking all these factors into account, an estimated maximum purchase price for this coin could be between 70 and 90 euros, given that the condition is good and the price history suggests that buyers are willing to pay more for coins in similar conditions.

Therefore, a reasonable maximum purchase price could be 80 euros.