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

1. Starting Price: 575.25 euros. This is the initial price set for the auction.
2. Auction History: The coin has been auctioned 19 times, of which it has sold 12 times. This indicates that there is interest in the coin, although there is also a 36.8% chance that it has not sold.
3. Average Starting and Hammer Price: The average starting price is 194.64 euros and the average hammer price is 262.14 euros. This suggests that, in general, coins of this reference tend to sell for a significantly lower price than the current starting price.
4. Condition: The condition of this coin is 85 (Near EF), which indicates that it is in fairly good condition, but not the best possible (FDC).

Given that the starting price is considerably higher than the average hammer price, and considering the condition of the coin, an estimated maximum purchase price could be set in a range that reflects both the quality of the coin and market interest.

Taking all these factors into account, an estimated maximum purchase price could be around 300 to 350 euros. This is based on the fact that, although the starting price is high, the sales history and average hammer price suggest that buyers might be willing to pay a little more than average, but not necessarily the full starting price.