I buy all of my blank media from 4 sources:
#1: My workplace. This is the most common, as I tend to get GOOD prices
#2: Various retail outlets located in my general area, mainly due to my workplace not carry EVERY brand of blank media, and I like a variaty
, they offer a nice variety, and have better prices then most stores do for DVDs, although I get better pricing on anything Ritek based from my workplace (which is what I personally use most of the time)
#4: Small shady flea market like operations. Why? because they don't charge the CD levy, and most of the time don't charge tax either, and when you are buying over 2 thousand CD-Rs a year, sometimes you want to cut a few corners! This is the most uncommon source for me, since I am also pretty picky about quality standards!
Punch Cards -> Paper Tape -> Tape Drive -> 8" Floppy Diskette -> 5 1/4" Floppy Diskette -> 3 1/2" "Flippy" Diskette -> CD-R -> DVD±R -> BD-R
The Progression of Computer Media