scrub
Why scrub?
Scrubs are used to clean up. To physically dislodge dirt so that the dirt can be washed away easily.
A facial scrub or body scrub exfoliates the skin as well. It would slough off the old skin that is dead, dull and possibly flaky, to reveal the younger, dewy skin beneath. On top of that, by cleaning up the gunk on the surface of the skin, it unblocks pores, which if left blocked would result in pimples.
Hence scrubs or at least exfoliation, is necessary for healthy, clear skin in the long run.
Facial Scrubs
The purpose of using a facial scrub is to exfoliate the skin. Exfoliation can be done either by rubbing solid particles against your skin or by the use of chemicals that dissolve the "glue" which holds the dead skin flakes to your skin. Healthy Pores, an acne treatment system, uses salicylic acid for exfoliation while facial scrubs might use ground almonds, jojoba beads or a myriad of mild abrasives to smoothen your skin. Either method would clean off the gunk, smoothen the skin and reveal younger, dewy skin. With acne, however, I would advise against physical scrubs and suggest you go with Healthy Pores instead as the abrasive scrubs might spread the infection. That said, for normal skin, a good facial scrub used weekly is a great way to keep your skin very clean.
Clinique has an excellent scrub which my mom uses when she wants to spring clean her skin. Someone at a dinner commented how young she looked and wanted to know her secret. I wanted to know too since I dread the day I look like her older sister, which would come soon if I don't do something fast. Genetics? Pah. She said the only thing she ever uses besides daily cleansing is Clinique 7 day scrub. She does the 7 day thing only now and then when she feels like it. Something like once in a few months. I bought that but use it once a week or in a few days or when I remember to do so. The texture is creamy and grainy and it rinses off completely with water.
Body Scrubs
Soft, smooth skin is beautiful. Dry, flaky skin is not. Body scrubs are used to slough off dead skin cells to reveal the younger skin beneath. They are usually a pleasure to use. Massaging in the scrub while you bathe is invigorating. Rinse off the scrub and your skin is left smoother and softer. Slather on moisturizer after that for a complete pampering experience. Besides, using body scrub makes one feel cleaner all over.
A loofah is just as good in the bath. Or you can try rubbing on Dead Sea Salt for an invigorating, mineral rich scrub.
The Body Shop scrubs range from loofahs to fruity scrubs you massage onto your skin. Personally, I prefer their creamy scrubs for the full pampering experience.
Pumice scrubs come in especially handy on rough elbows, knees and the soles of the feet. Daily use would lead to more attractive feet and elbows in the long run.
Other scrubs
Besides personal care scrubs, this page features other scrubs to keep your home clean. What's the point of stepping out of the shower, clean and fresh, into a room that's steep in dirt?
Going by brand, you'd find facial scrubs, body scrubs and other scrubs that basically get rid of the gunk.
Looking for the cheapest scrub product online?
This is what I've found.

Natural Facial Scrub, Apricot
Your Price $3.11

Natural Facial Scrub, Oatmeal 'N Honey
Your Price $3.11

Natural Facial Scrub, Mint Julep
Your Price $3.11
Most Discounts
If you want value for money, (I know I do) here are the ones with the highest discounts as a percentage of the original price.

Carita Diliuant for Scrub ( Salon Size ) 500ml/16.9oz
Retail Price $96.00
Your Price $60.50
Your Discount 36.98%
Highest dollar savings.
If you want to treat yourself to something special. Go ahead. With these savings, these luxuries are finally within your reach. This is where you can find the best dollar savings online.

Carita Diliuant for Scrub ( Salon Size ) 500ml/16.9oz
Retail Price $96.00
Your Price $60.50
You save $35.50