Amazon is the largest online retailer in the US and has been so for some time. With nearly 20 years of experience, they are experts in ecommerce on a mission to sell anything and everything. 128 million average Unique Monthly Visitors in the US. Amazon.com and other sellers offer millions of unique new, refurbished, and used items. Categories include: books, movies, music & games, digital downloads, electronics & computers, home & garden, toys, kids & baby, grocery; apparel, shoes & jewelry, health & beauty, sports & outdoor, and tools, auto & industrial.