To estimate a maximum purchase price for the coin with a grade of 80 (MBC+), we can analyze historical data and price trends.

1. Coin data from previous auctions:
- The grade of 80 (MBC+) has had auction prices that vary, but generally, the hammer prices for coins of similar grade have been in a range of 35 to 180 euros in previous auctions.
- For example, in past auctions, hammer prices of 35 euros have been recorded for a coin with a grade of 80 and up to 180 euros for coins with higher grades (95).

2. Average hammer price:
- The average hammer price for this coin has been 58.59 euros, indicating that, in general, buyers are willing to pay around this price.

3. Recent auction trends:
- The coin has been auctioned 205 times, of which 180 have been successful sales. This suggests that there is a consistent interest in this coin.
- The current starting price is 30 euros, which is relatively low compared to previous hammer prices.

4. Estimation of the maximum purchase price:
- Given that the grade is 80 (MBC+), and considering previous hammer prices and the interest in the coin, a reasonable maximum purchase price could be in the range of 70 to 90 euros. This is based on the fact that buyers may be willing to pay a bit more than the average hammer price, especially if there is competition in the auction.

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