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

1. Current Condition: The coin has a condition rating of 80 (MS+), indicating that it is in relatively good shape. This can positively influence its price.

2. Starting Price and Average Hammer Price: The starting price is 225 euros, and the average hammer price in previous auctions is 228.52 euros. This suggests that the hammer price tends to be close to the starting price.

3. Auction History: The coin has been auctioned 38 times, of which it has sold 34 times. This indicates good demand and sustained interest in the coin.

4. Previous Prices: By looking at previous hammer prices for coins with similar conditions, we can see that they have reached hammer prices that varied, but some have exceeded 200 euros, especially in higher conditions.

5. Recent Trends: In the most recent auctions, hammer prices have been quite high, with some reaching up to 650 euros in similar conditions.

Given all this, an estimated maximum purchase price could be in the range of 250 to 300 euros, considering that the condition is good and that interest in the coin seems to be high. This also takes into account the starting price and the history of hammer prices.

Therefore, a reasonable maximum purchase price could be approximately 280 euros.