I haven't experienced this myself (not having purchased seeds from a supermarket), but some gardeners report that supermarkets re-package "expired" seeds. Well, seeds don't really "expire," but their germination rates will decline as time marches on.
I would be very leery of "deals" like "10 packets for $1" and such.
I've ordered seed catalogues for next season and I actually ordered seeds from two sources this year. Each source guaranteed 80% or better germination in supportive conditions.
And, yes, the varieties available in supermarkets won't necessarily be the ones best suited to your growing locale.
USDA Zone 9, Sunset Zone 17