Amazon has a lot of bicycles for sale. Which ones are good? There's a lot of brands I never heard of.
https://www.amazon.com/Adult-Bikes-Cy...d_i=2232464011

I thought these were pretty good.

https://www.amazon.com/Advanced-SE-La...I3C4LYUBLH3JEG


https://www.amazon.com/Diamondback-20...I24UDRPXZF7PAW

What are the best bikes on Amazon for $500 or less?

I know that I will get flamed for this, but for $500, I would look at Bikes Direct if you are handy and a LBS if you are not. I wouldn't get it off Amazon.

Do they carry the same brands as Amazon?

iheartbacon no they do not carry the same brands as Amazon. check them out. I bought a 2012 Motobecane Fantom CX for commuting and I have been truly enjoying it. It is faster than my old commuting bike and it even feels more nimble.

I know that on the forums people talk down about them but I asked a question about sizing on a Saturday and traded emails with a rep. I then made my order Saturday and the bike was delivered by Thursday.

Pfft. This is an Amazon gem (read the reviews): https://www.amazon.com/Victorio-Kitch...pr_product_top

^ Wishlisted.