Should I buy bulk groceries on Amazon or Costco?

For most shoppers, the better choice depends on what you value most:

• Pick Costco if your main goal is value on common bulk staples. Costco is often very competitive on per-unit pricing for many household basics, but it is not guaranteed to be cheaper on every item.
• Pick Amazon if you want convenience, delivery, or a broader mix of specialty items. Amazon can be better for doorstep delivery, easier reordering, and some harder-to-find or dietary-specific products. It can also be competitive on price for certain items, especially if you compare unit prices carefully.

A good rule of thumb is: Costco for big, repeat purchases; Amazon for convenience and specialty needs. If you want the best deal, compare the price per ounce, count, or sheet and factor in shipping, taxes, and any membership or subscription fees. Exact savings vary by product and current pricing, so it is worth checking both before buying.