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 has been 94.53 euros.
- In previous auctions, coins with a similar condition (75) have reached hammer prices of up to 90 euros (as seen in the auction on 2020-12-16).

3. Starting Price and Average Starting Price:
- The current starting price is 30 euros, which is relatively low compared to the average hammer price.
- The average starting price of 46.93 euros also suggests that there is room for the hammer price to be significantly higher.

4. Recent Trends: In the most recent auctions, the hammer price has varied, but there are examples where coins with similar conditions have reached hammer prices ranging from 70 to 140 euros.

Based on these factors, an estimated maximum purchase price for this coin could be in the range of 90 to 120 euros. This is based on the historical hammer prices for coins of similar condition and the average hammer price observed. However, since the market can be volatile and depends on demand at the time of the auction, it is advisable to be prepared to adjust the bid according to the competition in the auction.