do you mean a carpet cleaning machine or just a product? :Z
theres a vanish carpet foam that does a brilliant job, i use mine all the time *clumsy*
if you mean a machine i borrowed a vax one from the in laws and it worked really well...but not amazing tbh...
http://www.qed-uk.com/electricals/product/vax/ v027.html?&ird=1117 they got theirs for �100 from costco.
or you can hire beasty ones from homebase for about �30 (take a utility bill with you) and my friends use them a couple of times a year and swear by them
x