Easy to store at work and lasts a long time would be a jar of peanut powder to mix in things like yogurt. Jif has come out with their version of PB2.  Right now, it is  20% off at Target with their cartwheel program.  Stack it with a $1 printable found at coupons.com making for a total cost under $3.  

Smart AND Frugal!  You must be Minnesotan!  ;)  Thank you!

Roasted edamame.  ( I think I spelled it correctly.)  Some grocery stores sell them in the produce section.  You can also get them at health food stores.  They satisfy that need to crunch!