Based on the provided data, we can observe that the coin in question has a grade of 80 (MBC+), indicating that it is in fairly good condition. Additionally, it has been auctioned in the past on several occasions, with varying starting and estimated prices.

The average starting price of this coin in previous auctions has been 29.58 euros, while the average closing price has been 25.99 euros. However, in one of the previous auctions, the coin reached a closing price of 27.53 euros with a grade of 80.

Taking into account these data and the history of previous prices, as well as the current condition of the coin, we could estimate a maximum purchase price around 30-35 euros. Since the highest closing price was 27.53 euros, we could consider an additional margin for a possible bid in a future auction.

Therefore, an estimated maximum purchase price for this coin in the next auction could be around 30-35 euros.