have you researched the "cause" of "fresh" stuff going "bad"?
the biggies: moisture & oxygen
the contenders: age and light
there are two "perfect barriers" to moisture and oxygen:
all the fancy plastics and co-hi/lo-extruded films, metallized and not, are attempts at being "better" barriers. some are decent, some are not so good.
you've probably heard the ole party line "throw out / replace your spices after a year." that is whistles in the wind for about 99.999999999999996% of home kitchens.
so, offer an initial purchase in a glass-with-metal-lid jar - and a prominent explanation of "why" - with purchase also offered in sealed foil packets.