Why don't you look at the original post. Really, does this sound like someone who intends getting into carpet cleaning " full time " or just considering the possibility of having a machine available for the odd job ?
Rather than give mis information, or prejudiced information, from narrow viewpoints, I suggest you consider the following.
Do you really want to get into carpet cleaning
Who will do the c/cleaning for you
Have you considered that the carpet cleaning will be done separately from the other tasks, which means you will need additional transport, or have to back track, or whatever.
Of course it can be done, but just lumping it on to other cleaning tasks won't work. Not trying to put you off, just want you to think through the logistics and potential costs and the likeliehood that it will be a separate entity from your day to day activities.
If you really want to have a go.............
The suggestions above, will require an outlay from under £1k to well over £20k
And..................there are methods which will more than adequately clean carpets and have them touch dry in 30 minutes.