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+), which indicates that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Historical Prices: By looking at previous auction prices for coins with similar conditions, we can see that the hammer price has varied. For example, in past auctions, coins with a condition of 80 have reached hammer prices of up to 80 euros.

3. Average Hammer Price: The average hammer price for this coin is 85.84 euros, which can also serve as a reference.

4. Starting Price and Average Starting Price: The current starting price is 35 euros, and the average starting price is 97.72 euros. This suggests that there is potential for an increase in the hammer price.

5. Recent Trends: In the most recent auctions, hammer prices have shown an increase, especially for coins in good condition.

Taking all these factors into account, an estimated maximum purchase price for this coin could be around 90-100 euros. This is based on the current condition, previous hammer prices, and the general trend in the market.