Please advise me of the cost.

请把价钱通知我。

Please advise your fax number.

请提供传真号码。

Please advise on how I can do this.

请告知我如何可以做到这一点。

Please advise the date of delivery.

请告知发货日期。

Please advise me which is the best.

请告诉我哪个最好。