Based on the provided data, we can observe that the coin has had an average auction closing price of 36.32 euros in previous auctions. Additionally, the current condition of the coin is graded at 90 (EBC).

Considering that the estimated maximum purchase price is usually slightly higher than the average auction closing price, and taking into account the condition of the coin, we could estimate a maximum purchase price around 40-45 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 stay alert during the auction to adjust the offer accordingly.