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 relatively good shape, but not of the highest quality (FDC).

2. Historical Prices:
- The average hammer price for similar coins has been 115.67 euros.
- In previous auctions, hammer prices for coins with similar conditions (75-80) have varied, with some examples being:
- 55 euros (2020-12-15)
- 90 euros (2020-07-02)
- 70 euros (2017-10-24)
- 130 euros (2023-01-31)

3. Sales Trends: The coin has sold in 53 out of 59 auctions, indicating good demand.

4. Starting Price: The starting price is 30 euros, which is quite low compared to previous hammer prices.

5. Average Starting Price: The average starting price for similar coins is 63.3 euros, suggesting that the current starting price is competitive.

Given all this, an estimated maximum purchase price could be in the range of 90 to 130 euros, considering that the condition is 75 and there are examples of previous hammer prices in that range. However, to be more conservative and taking into account the variability in auctions, a reasonable maximum purchase price could be 100 euros. This allows for a margin for competition in the auction and the possibility that other bidders may also be interested.