There is something to be said for exclusive salon products and department store make-up. There really is. But I am not against using drug-store brands. For instance, I've used every facial cleanser you can think of - paid as much as $200 for a skin care regime (yonka, murad - you name it I've probably tried it) but I just keep coming back to gool ole Cetaphil. $10 for a big bottle of the "Galderma" and a washcloth and I love it. I started using it because a doctor recommended it to my mom for her rosacea and I figured, genetically, I might be at risk too so I better start early. It's gentle, moisurizing without feeling heavy and it cleans my skin and removes make-up great.
Shampoo and conditioner is another story. That has to be considered on a case by case basis. If you are spending money having your hair colored, a $20 bottle of shampoo is really just protecting the investement you've already made in your hair. If you spend $200 on amazing color and then wash it with an inexpensive shampoo with wax and sulfates you should not be suprised the color fades quickly. If you are blonde - not SUCH a big deal, since you want to remove pigment from the hair, but it could mess with the tone. For instance, Pantene: I actually love Pantene. It makes your hair feel super soft and shiny, but I would only recommend it to someone who has natural (non-colored) hair. Pantene will coat your hairshaft (which helps it feel good) but coating and rinsing over and over is like putting a mud mask on your face, it just sort of sucks the color out. This can be usefull if you colored your hair darker than you wanted - I did that once, colored it black and hated it so I used Pantene for a month and ended up about a shade and a half lighter. Great! But like I said, it's a case by case thing. Some of my clients just don't like to spend a lot on hair products so I like to be educated on what's available as a "drug store alternative." That's just the way I roll - I'm not a "Salon Product" snob. *But* I must also say, that salon hair products just outperform drugstore hair products, hands down, on the whole, every time. Still, it is "just hair" and for people who don't have hair on the top portion of their bugetary priorities, there is probably a good enough drug store brand available that will do the job well enough.
There are few exceptions where the inexpensive, tried and true drugstore brand just gets it right on, but it does happen. One example is Clairol's "Shimmer Lights" shampoo. If you are a bleached blonde who tends to get yellow - this shampoo is hands down the best you can get. ArtTech is close, but Shimmer Lights is much less expensive and, I think, works better. It's good for getting white hair silver too...

note: I am not inferring that Meryl, Emmylou or Helen use Shimmer Lights. I just think posts with photos are way more interesting!