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

1. Starting price: 1400 euros.
2. Current condition: 80 (MBC+), which is a fairly good condition, although not the highest.
3. Auction history: The coin has been auctioned 8 times and has sold on all occasions, indicating a constant interest in the coin.
4. Average starting and hammer price: The average starting price is 1085.71 euros and the average hammer price is 1587.5 euros. This suggests that, in general, coins of this reference tend to sell for above their starting price.
5. Previous hammer prices: Hammer prices in previous auctions have varied, but there are examples of hammer prices reaching up to 3000 euros for higher conditions (95).

Given that the condition of the coin in question is 80, which is lower than the higher conditions that have reached higher hammer prices, but still an acceptable condition, we can estimate a maximum purchase price.

Based on the average hammer price (1587.5 euros) and considering that condition is an important factor, a reasonable maximum purchase price could be in the range of 1600 to 1800 euros. This is because the starting price is 1400 euros and the interest in the coin seems to be strong, in addition to the auction history suggesting it could reach a price above average.

Therefore, an estimated maximum purchase price could be 1700 euros.