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 80 (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:
- It has been auctioned 13 times in the past, of which it has sold 6 times. This suggests that there is moderate interest in the coin.
- The average starting price in previous auctions is 46.54 euros, and the average hammer price is 48.17 euros. This indicates that, in general, coins of this reference tend to sell close to these values.

3. Previous Prices:
- In past auctions, hammer prices have varied. For example, in 2014 it sold for 70 euros with a condition of 90, indicating that a higher condition can lead to significantly higher prices.
- In other auctions, with lower conditions (75), the hammer prices have been lower, such as 35 euros.

4. Current Starting Price: The starting price is 50 euros, which is a good starting point.

Given that the condition of the coin is relatively good (80), and considering the history of hammer prices and interest in the coin, an estimated maximum purchase price could be positioned above the average hammer price.

Estimated Maximum Purchase Price:
We could estimate a maximum purchase price around 70-80 euros. This is based on the fact that, although the average hammer price is lower, the good condition and interest in the coin could justify a higher price in this auction.