A 16 oz can of NOS (Nitrous Oxide Systems) Loaded Cherry has high taurine levels and packs a hefty kick with 160 mg of caffeine. What makes NOS stand out is large amounts of L-Theanine, a substance found naturally in tea, said to offset the negative effects of caffeine without dulling the positives. NOS is available from Walmart and retails for $1.68 per can.