Amazon USA is a vast online marketplace and ecosystem — a place to buy almost anything (from books to groceries), stream media, get fast delivery, and access subscription services. This guide explains Amazon’s major categories and businesses, how the platform works at a high level, practical, battle-tested ways to save money when shopping on Amazon, and common FAQs. Wherever I make claims that can change over time (programs, features, official pages) I’ve added sources so you can verify details.

What Amazon USA is — the big picture

Amazon.com began as an online bookstore and grew into a global e-commerce platform, logistics company, streaming and cloud services provider, and more. In the US it operates as:

• A retail store (Amazon Retail) that buys and sells inventory.
• A marketplace that hosts millions of third-party sellers (3P sellers) offering new, used, and refurbished goods.
• A subscription platform (Prime) that bundles delivery, video/music/eBooks, and other perks.
• Grocery and daily-needs offerings (Amazon Fresh and Whole Foods Market).
• Specialty services for businesses (Amazon Business), developers (AWS), creators (Kindle Direct Publishing, Amazon Stores), trade-in, and refurbished/resale channels (Warehouse/Resale).

Because Amazon is both a retailer and a marketplace, prices and options can vary widely between sellers and even between different product conditions (new, like-new, open box, refurbished, used). This creates great opportunities to save — but it also means smart shopping pays off.

Amazon’s main categories (high level)

Amazon organizes its store into departments so shoppers can quickly drill down. These are the broad categories you’ll see on the US site and that capture most product types:

• Electronics & Computers — phones, laptops, TVs, accessories, cameras.
• Home & Kitchen — furniture, small appliances, décor, bedding.
• Clothing, Shoes & Jewelry — men, women, kids, accessories.
• Beauty & Personal Care — skincare, makeup, grooming.
• Grocery & Gourmet / Amazon Fresh / Whole Foods — groceries, pantry items, fresh produce (local availability matters).
• Health, Household & Baby Care — medicine, household supplies, baby goods.
• Books, Audible & Kindle — physical books, eBooks, audiobooks.
• Toys & Games / Sports & Outdoors — toys, outdoor gear, fitness equipment.
• Tools & Home Improvement / Industrial & Scientific — power tools, hardware, pro supplies.
• Pet Supplies, Office Products, Automotive, Musical Instruments and many more specialized subcategories.

Amazon’s navigation lists dozens of departments and sub-departments so you can shop by very specific niches. These primary departments shape search results, filtering, and the storefronts you’ll encounter.