Based on the data provided, we can observe that the coin in question has had an average auction closing price of 99.48 euros in previous auctions. Additionally, the current condition of the coin is 80 (VF+).

Considering that the coin will be auctioned in the upcoming days and has had an average starting price of 55.4 euros, we can estimate a maximum purchase price based on the history of previous auctions and the current condition. Given that the average closing price has been 99.48 euros, and considering the current good condition (80), we could consider an estimated maximum purchase price around 110-120 euros.

It is important to note that the final auction price may vary depending on the demand at that specific moment, so it is advisable to pay attention to the auction to adjust the offer accordingly.