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

1. Starting price: 500 euros.
2. Average starting price: 1050 euros.
3. Average hammer price: 2575.68 euros.
4. Auction history:
- In 2011, it was sold for 3800 euros.
- In 2012, with a condition of 75, it was sold for 2800 euros.
- In 2021, also with a condition of 75, it was sold for 3062.73 euros.
- In 2022, it was estimated at 2953.47 euros with a condition of 75.

Since there is no information about the condition of the current coin, it is difficult to make a direct comparison. However, we can observe that coins with a condition of 75 have reached hammer prices between 2800 and 3062.73 euros.

If we consider that the current coin might have a similar or better condition, we could estimate a maximum purchase price based on previous hammer prices.

A reasonable approach would be to take the average hammer price of coins with a condition of 75, which is approximately 2885.36 euros (average of 2800, 3062.73, and 2953.47).

Given that the starting price is 500 euros, and considering that the market may be willing to pay a higher price, a maximum purchase price could be around 2885 euros, although it might be wise to adjust this figure downward to account for uncertainty regarding the condition.

Estimated maximum purchase price: 2800 - 3000 euros.