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 90 (EF), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Starting Price and Average Hammer Price: The starting price is 2000 euros, and the average hammer price in previous auctions is 2361.76 euros. This suggests that, in general, coins of this reference tend to sell for above the starting price.

3. Auction History: In the auction history, it is observed that the coin has had hammer prices that varied, but on several occasions, it has exceeded 2000 euros, even reaching up to 4400 euros in a recent auction (2023-03-16) with a condition rating of 95.

4. Price Trends: Hammer prices have shown an upward trend in recent years, especially for coins in good condition. The last auction with a hammer price of 4400 euros suggests that there is growing interest in this coin.

Based on these factors, an estimated maximum purchase price could be set in a range between 3000 and 3500 euros, considering that the coin's condition is good and that interest in this type of coin seems to be increasing. This also allows for a margin for competition in the auction.