wz adrenals and medpacks whenever you near the comms cap
This if you already have the lvl 20 items you want, move onto getting the lvl 40 items you want. Then when you have all that spend everything else on adrenals and medpacks until you hit 40 then convert into ranked comms. They store up the max for right before you hit 50. Then you can usually buy a few elite war hero items and almost a full set of War hero, and have the medpacks and everything for plenty of rounds of PvP.