To estimate a maximum purchase price for the coin in question, we can analyze the provided data, especially the previous auction prices and the current condition of the coin.

1. Current Condition: The coin has a condition of 75 (VF), indicating that it is in fairly good shape, but not the best possible condition.

2. Previous Auction Prices:
- In previous auctions, the hammer prices have varied depending on the condition. For example:
- A coin with a condition of 80 was auctioned for 320 euros (2020-01-23).
- Another with a condition of 85 was auctioned for 440 euros (2024-05-30).
- A coin with a condition of 70 was auctioned for 280 euros (2022-04-27).
- The trend shows that as the condition improves, the hammer price also tends to increase.

3. Average Hammer Price: The average hammer price for this coin is 311.79 euros, which can serve as a reference.

4. Starting Price: The starting price is 350 euros, indicating that the seller expects a higher price.

Given that the condition of the coin is 75, which is lower than the conditions of 80 and 85 that have reached hammer prices of 320 and 440 euros respectively, we can estimate that the maximum purchase price should be in a range that reflects its condition and market interest.

Estimation of the Maximum Purchase Price: Considering all these factors, a reasonable maximum purchase price could be between 300 and 350 euros, with 350 euros being the starting price. However, since the average hammer price is 311.79 euros, a more conservative maximum purchase price could be approximately 320 euros. This allows for some competition in the auction while also reflecting the condition of the coin.