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 75 (VF), indicating that it is in acceptable shape, but not among the best qualities. This generally affects the price, as coins in better condition tend to fetch higher prices.

2. Auction History:
- The average hammer price for similar coins in the past is 335.6 euros.
- The last auction for this coin had a hammer price of 460 euros with a condition rating of 95, indicating that the price can vary significantly based on condition.
- In previous auctions, hammer prices have ranged from 220 to 650 euros, depending on condition and other factors.

3. Starting Price: The current starting price is 300 euros, which may indicate the seller's expectations.

4. Price Trends: Observing the hammer prices of coins with similar conditions (70-80), the price range has been approximately 220 to 400 euros.

Given all this, an estimated maximum purchase price for the coin in its current state (75 VF) could be in the range of 350 to 400 euros. This is based on the auction price history and the current condition, as well as the price trends in previous auctions.

Therefore, a reasonable maximum purchase price could be 400 euros.