To estimate a maximum purchase price for the coin in question, we will consider several factors:

1. Current Condition: The coin has a condition of 75 (MBC), which indicates that it is in fairly good shape, but not of the best quality (FDC).

2. Auction History:
- The average hammer price for similar coins has been 84.45 euros.
- In previous auctions, we have seen hammer prices that varied significantly, but some relevant examples are:
- A coin with a condition of 80 was sold for 130 euros.
- Another with a condition of 85 sold for 120 euros.
- A coin with a condition of 70 sold for 65 euros.

3. Starting Price and Average Starting Price:
- The current starting price is 50 euros, and the average starting price in the past has been 56.24 euros.

4. Recent Trends: In the most recent auctions, hammer prices have shown an increase, especially for coins in good condition.

Based on this data, an estimated maximum purchase price for this coin could be between 90 and 120 euros. This is justified by the condition, the auction price history, and the upward trend in the market.

Therefore, a reasonable maximum purchase price could be 100 euros.