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

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

2. Auction History: By looking at previous hammer prices for coins with similar conditions (75), we can see that they have reached hammer prices of up to 95 euros (as in the auction on 2015-12-16).

3. Average Hammer Price: The average hammer price for this coin is 62.58 euros, which is also a good indicator of the expected value.

4. Starting Price and Average Starting Price: The current starting price is 45 euros, and the average starting price is 47.61 euros. This suggests that the starting price is reasonable and could attract bidders.

5. Recent Trends: In the most recent auctions, hammer prices have been in the range of 55 to 75 euros for similar conditions.

Taking all these factors into account, an estimated maximum purchase price for this coin could be around 80-90 euros. This is based on the historical hammer prices for coins of similar condition and the current state of the coin.