To estimate a maximum purchase price for the coin in question, we can consider several factors based on the provided data:

1. Current Condition: The coin has a condition rating of 75 (MBC), indicating that it is in quite good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Auction History:
- The average hammer price for similar coins in the past is 52.24 euros.
- The last auction for this coin had a hammer price of 55 euros (in 2021), suggesting that interest in this coin remains strong.
- In previous auctions, hammer prices have varied, but there are examples of sales reaching up to 130 euros (although this may be an exceptional case).

3. Starting Price and Average Starting Price:
- The current starting price is 30 euros, and the average starting price is 31.71 euros. This indicates that the starting price is aligned with market expectations.

4. Recent Trends: In the most recent auctions, hammer prices have shown a range from 30 to 90 euros, depending on the condition and interest from collectors.

Based on these factors, an estimated maximum purchase price could be in the range of 70 to 90 euros. This is because, given the condition of the coin and historical interest, it is reasonable to expect that collectors would be willing to pay a price above the average hammer price, especially if the coin is sought after.

Therefore, an estimated maximum purchase price could be 80 euros.