Professional Carpet Cleaning need not cost a fortune, however buying a really cheap service you might be really disapponted and think you may have wasted your money.
Carpet cleaning prices usually range from £2 to £5 per square metre, depending on how much work is involved.
For example: 2 identical carpets that should take an hours work if the property is on the ground floor with outside parking, could take 4 hours if the said carpet is on the 13th floor of a block of apartments with no parking facility nearby.
Also the more staining the carpet has, the more time and effort is needed to restore the carpet to a 'like new' condition.
As a general rule of thumb, £30 per room is somewhere near what you should be paying.