Sands and Oils are buyable in Revenent's Toll. But that involves getting 2 blood stained hunting logs for oils and 3 for sands which can only be obtained by using the allied guild seals you get from "Hunts".

So you ultimatly have three options. Grind Sycrus Tower (Which you're obviously doing), Grind the Second Coil of Bahamute (Assuming you've beten T5, which if you have Honesty Post Echo T7 is a total joke and easy as hell to farm), or do hunts for days to earn enough seals to buy ONE of the time items you want. (And there's a reason people farm ST and T7 rather than that)