Years ago, when I was a full time Mom of three little ones, a 100 lb. dog and living in a house with white carpet, I discovered an affordable way to 'clean' our carpets without forking over $100 to a carpet cleaner and dealing with the hassle of moving furniture and putting up with wet carpets for hours until they dried.
At the time I tried a moist/dry powder cleaner that you sprinkled on the carpet, brushed in, let dry completely and then vacuumed up. I thought it worked well and since it was available just down the street at my local DIY hardware store, I always had nice looking carpet even though I had three children under 5.
Our next two homes had more wood floors than carpeting and I forgot about the product for awhile. I remembered it last month when I was hunting and searching for a reputable carpet cleaner with decent prices to clean our white carpets in our current home. What I found was that almost none of them moved furniture (you have to have it moved yourself before they arrive) and then of course I knew I'd have to move furniture back and deal with the damp carpet in the meantime (with three kids and 2 cats....).
That's when I remembered the powder I used to use 10 years ago and tromped off to the local hardware store to see if they still sold it. They did... sort of.
It's sold under a different name now. It's currently called "Capture" Rug and Carpet Cleaning
You vacuum the area to be cleaned.
Spray the included spray to help loosen the fibers.
Sprinkle the moist/dry powder.
Brush in.
Let dry.
Vacuum up.
I was happy with the results and even purchasing as much of the product as I did, it still rang in at about 1/3 - 1/4 the cost of a traditional carpet cleaner would have been. Of course, it's only as good as the sucking power of your vacuum! But I have a Dyson
Overall I give it a thumbs up. If you have heavily soiled carpet, it hasn't been cleaned for 10 years or it's unusually trampled, smelly or have pet accidents I'd go with a traditional carpet cleaning first and then follow up every 6 months or so with this 'dry' carpet cleaning kit to keep it fresh and clean inbetween deep cleans.