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 (MBC), indicating that it is in relatively good shape, but not of the highest quality (FDC).

2. Auction History:
- The average hammer price for similar coins in the past is 320.65 euros.
- In previous auctions, hammer prices have varied significantly, with some reaching up to 1300 euros in superior conditions (such as in the March 2023 auction with a condition of 95).
- The last auction for this coin in December 2022 had a starting price of 175 euros and an estimated price of 250 euros, although the final hammer price is unknown.

3. Price Trends:
- The overall trend shows that hammer prices have been increasing, especially for coins in better condition.
- The coin has been auctioned 34 times, with a sell-through rate of 94% (32 out of 34), indicating consistent interest in this coin.

4. Current Starting Price: The starting price is 175 euros, which may be a good starting point for the estimation.

Given all this, an estimated maximum purchase price could be in the range of 300 to 400 euros, considering that the condition is 75 and that there is high interest in the coin. This is based on the average hammer price and the price trend in previous auctions.

Therefore, a reasonable maximum purchase price could be 350 euros.