What is the difference between a sock monkey and Sock Monkey?
This is a sock monkey.

I did not invent it. No one knows who made the first sock monkey. It has been decreed by the United States government that sock monkeys are part of the public domain. (I learned this at the Midway Village Museum, in Rockford, Ill., the one-time home of the red-heeled sock plant that made the socks that folks used to make the monkeys.)
This one sold for $29.99 on Amazon, in conjunction with the Mr. Magorium movie. That’s a lot of money for something you can make yourself from a pair of socks.
Yes, a sock monkey is a monkey made from socks. (Although some pre-fabricated monkeys were likely never socks.)
You can make your own sock monkey. (And you should if you want a really great sock monkey.)
You can buy a kit: 
Or use your own socks and online instructions.
There are many thousands of sock monkeys. You can see wonderful pictures of some of them in this book by Ron Warren and Arne Svenson:

Sock Monkeys: 200 out of 1863
(We love this book!)
Now here is Sock Monkey (note the capital letters.)

There is only one Sock Monkey. He is a sock monkey named Sock Monkey. He stars in a series of picture books by Cece Bell.

Sock Monkey Rides Again: “Kids will giggle, and moms and dads won’t mind reading this tale again and again. And again.” — Entertainment Weekly online, ew.com
Furthermore, he is a famous toy actor, whose latest starring role was “Red Reardon” in The Happy Canyon Hoedown. (see Sock Monkey Rides Again).
Sock Monkey himself has made a sock monkey. That sock monkey was made from argyle socks, likes cupcakes and named himself “Sock Buddy.” (see Sock Monkey Boogie Woogie).
Sock Monkey has three other friends, Miss Bunn, Blue Pig and Froggie who are also free-willed toys. (see Sock Monkey Goes to Hollywood).

Of course, these books only feature drawings of Sock Monkey, which I hope are entertaining!
Sock Monkey is indeed a real sock monkey, who lives with me. He is frequently photographed, but his photo is rarely seen online. Though you may find it on this website if you look around a bit…