Co-op grade-A vanilla is less expensive because your order is bundled with other orders to save on costs. Orders with products labeled "co-op" usually ship in 4-6 weeks.
Retail grade-A vanilla is more expensive because it is warehoused and ready to ship. Retail orders that are not coupled with co-op orders will ship in 2-5 days.
Grade-A vanilla beans are great for virtually anything vanilla. Use them in homemade vanilla extract, vanilla powder, vanilla bean paste, vanilla sugar, etc. You can slice them open to harvest the beautiful caviar for use in frostings and vanilla bean ice cream and so much more.