Based on the provided data, we can observe that the coin in question had a starting price in the most recent auction of 600 euros, with an estimated price of 1000 euros and a closing price of 600 euros. The condition of the coin has been described as 80 (MBC+).

Additionally, we have seen that in previous auctions, the starting and estimated prices have varied, with closing prices also fluctuating. However, on average, the closing price has been 613.75 euros.

Given that the coin will be auctioned in the coming days and considering its auction history, condition, and previous prices, we could estimate a maximum purchase price of around 1000 euros, which is the most recent estimated price and close to the average closing price.

Therefore, an estimated maximum purchase price for this coin in the next auction could be around 1000 euros.