good carpet cleaning products?

Im thinking of maybe just buying a black carpet from Wal Mart with no jute instead and just cutting and trimming it to fit, and buying a roll of insulation from home depot (my dad bought a roll for 25 at home depot and it makes a world of differnece inside the car- heatwise and noisewise)....i really dont want to drop $140 on a brand new carpet so i think i mite go this route....has anyone else done something like this before?