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:
- The average hammer price for this coin in the past is 330.25 euros.
- In previous auctions, hammer prices have varied, with some reaching up to 1000 euros in exceptional conditions (such as in the auction on 2016-11-10).
- The last auction with a known hammer price was 420 euros on 2024-05-30.

3. Starting Price and Average Starting Price:
- The current starting price is 300 euros, which is slightly higher than the average starting price of 250.98 euros. This may indicate an expectation that the coin will sell for a higher price.

4. Recent Trends: In the most recent auctions, hammer prices have been in the range of 270 to 500 euros, suggesting that there is growing interest in this coin.

Based on these factors, an estimated maximum purchase price could be in the range of 400 to 500 euros, considering that the condition is good and that interest in the coin seems to be increasing. Therefore, a reasonable maximum purchase price could be 450 euros.