Where is the best place to buy vinyl?

I've heard people ask a lot, where is the best/ cheapest place to buy vinyl?
I broke down all the prices from popular vinyl suppliers sites and figured out which is the best deal.


(Here is the 2019 Update)

Here are the results:
Vinyl (solid colors):
Champion Sign Supply for 651, 24" x 360" is $27, which comes out to .003 cents per inch. 

Patterned Vinyl:

Solid Heat Transfer Vinyl:

Patterned Heat Transfer Vinyl: