Hoover has a very basic carpet shampooer that runs about $150. It's got a clean water and detergent tank and a dirty water tank. Run it like a vacuum. You can mix oxyclean in it- that takes up just about anything, including somethign bright purple that my sister had spilled under her bed when she was staying with me- didn't find it until she moved.
Also, if you boil water on the stove, add oxyclean, pour it over the stain and scrub, then suck it up. This worked to get up dog pee, among other things. We had a rental and cleaned the carpets with this shampooer almost every weekend and when we got our own house, with brand new (bottom of the line) carpet- using this cleaning process helped carpet designed to last 3-5 years make it 9 years.
Michelle -mom to Katlyn 4/00 , Jake 3/02, and Seth 5/04