Online "deals" often charge ridiculous amounts for shipping. I purchased seeds last year, knowing that I'd have enough for two and possibly three years because of the tiny amount of growing space I have.
Averaging it out over 3 years, I did pretty well, *especially* in the shipping department.
Bix Box stores, although they may have apparently low prices, generally have varieties of seeds which do well in a mythical "average garden." But the climate, soil, sun, rain/drought, etc. conditions each gardener deals with are exceedingly local, so I recommend seeking out local sources for seeds if you can't find the varieties you want elsewhere for a decent price.
Sunset Zone 17, USDA Zone 9