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

1. Condition: The coin has a condition rating of 95 (EF+), indicating that it is in very good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction History:
- The average hammer price in previous auctions is 19.5 euros.
- In recent auctions, hammer prices have reached up to 60 euros (in December 2021) and 39 euros (in April 2018) for coins of similar condition.
- In the most recent auction with a condition of 95, the hammer price was 30 euros.

3. Starting Price and Estimates:
- The current starting price is 12 euros, which is reasonable given the price history.
- The estimated price in previous auctions has varied, but it has reached up to 30 euros on some occasions.

4. Trends: The general trend seems to be that coins in EF+ condition tend to sell above the starting price, especially if there is interest in the auction.

Based on these factors, an estimated maximum purchase price for this coin could be between 25 and 35 euros, considering that the condition is high and there is a history of hammer prices that supports this estimate.

Therefore, a reasonable maximum purchase price could be 30 euros.