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

1. Coin 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:
- The average hammer price for coins with a similar condition (80) has been approximately 49.67 euros.
- In previous auctions, the hammer price has varied, with a maximum of 110 euros in a recent auction (2023-02-16) for a coin with a condition of 90, indicating that there is a market willing to pay high prices for well-preserved coins.

3. Starting Price and Previous Prices:
- The current starting price is 30 euros, which is slightly higher than the average starting price of 25.3 euros. This may indicate an expectation that the coin will sell for a higher price.
- In previous auctions, the hammer price for coins with a condition of 80 has ranged between 30 and 105 euros.

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

Based on these factors, an estimated maximum purchase price for this coin could be around 70-80 euros. This is based on the historical hammer prices for coins with similar conditions and the current market trend.