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

1. Current starting price: 1500 euros.
2. Coin condition: 95 (EBC+), indicating good condition.
3. Auction history:
- The average hammer price in previous auctions is 1651.5 euros.
- In previous auctions with similar condition (95), the hammer prices have been 2500 euros (2023) and 2400 euros (2024).
- The trend shows that coins in good condition tend to sell for above the starting price.

4. Analysis of previous prices:
- The coin has had a hammer price of 2500 euros in a recent auction with the same condition.
- The lowest hammer price in previous auctions with similar conditions has been 1300 euros.

Given that the coin is in good condition and the price history shows that similar coins have reached high hammer prices, an estimated maximum purchase price could be set in a range between the average hammer price and the highest price reached in the past.

Estimated maximum purchase price:
We could consider a maximum purchase price of around 2400 euros, which is a conservative value but reflects the potential of the coin based on its condition and auction history.