These companies often say the only catch is that you have to agree to allowing a number of visitors to see the work after the job has been carried out. But Tony Northcott, of the Institute of Trading Standards, says: "We've had a fair number of complaints about these deals. The idea is often that you take out a loan for a deposit and the company promises to send round a certain number of people: you then get paid for each one. But often no one ends up coming and you pay for the lot yourself."
Kitchen companies often say the reason they can offer such amazing deals is that they are saving money by not having a showroom. But Grahame Morrison, of the Kitchen Specialists Association (KSA), says: "It's usually a load of cobblers. You should never ever buy a kitchen from a company that doesn't have a showroom. I just can't stress it enough. There are almost always hidden costs."
For new kitchens, Mr Morrison advises taking out deposit protection insurance, which can be bought via the KSA. This will cover you should the company go under or try to rip you off.
If it's double glazing you're after and you come across what appears to be a brilliant offer, always make sure the company concerned is a member of the Glass and Glazing Federation. This organisation will carry out free conciliation for you should anything go wrong, and your deposit will be automatically protected.
But there are freebies - or at least cheapies - to be had for your home. An excellent way to get a new, cheap kitchen is to buy a display model. It will usually be in good condition and, says Mr Morrison, "the amounts saved that way can be substantial."
Thinking a bit more laterally, you can have your house done up on the cheap by combining it with your 15 minutes of fame; just get yourself and your four walls on one of the home makeover programmes on television.
Allison Edwards, a 34-year-old housewife from Shropshire, is going to appear in the next series of the BBC's daytime show Real Rooms, in which a room in her converted police station is made over by a team of experts. The subject has to pay no more than pounds 500 and the only catch is that you don't get to see what's happening until the grand unveiling at the end. But Ms Edwards was delighted with the results.
"It was breathtaking what they did with the place. It looks fantastic," she says. "We got at least pounds 2,500 worth of work, plus all the expertise, for just pounds 500. And they do really make sure they understand your taste first. There was only one small thing I didn't like and it was easily painted over."
In the BBC's hit series Changing Rooms, where two couples swap houses to decorate them, there's also a pounds 500 budget. But in this case the programme covers it, so it really is a freebie. The producer, Ann Hill, says: "You don't have to pay anything apart from your blood, sweat and tears." There was one famous episode - described by Ms Hill as "truly painful TV" - when the people concerned were horrified by what had been done, but generally the response is very positive.
You will not necessarily get picked if you write in, but as Ms Hill says: "We are always on the look-out and are by no means fully booked up." The criteria are that you must have a room larger than 12 feet by 12 feet, and you and your chosen friends must live no more than five minutes away from each other.
Needless to say, being completely comfortable with their taste is highly recommended.
You could stick with the media approach and also try to get in on a reader make-over in a homes and interiors magazine.
But take care, this is not always the great deal you might imagine. A homes editor on one big women's magazine warns: "There can be loads of hidden problems and it can end up being a real nightmare. You might end up paying more than you'd envisaged, and also you may have to have things done in a way that you don't want."
It can work out well, just as long as you're prepared to be flexible and you have the right kind of room. The new title BBC Good Homes is on the look-out for potential reader homes and editor Julie Savill says there are some good discounts available; kitchens may be up to 40 per cent cheaper and the paint and fabrics used are often free. You have to do the work yourself, but you'll get expert advice along the way. Ms Savill says: "The number of people writing in is building up fast, but a lot of people want their kitchens and bathrooms done. We're interested in other bits of the house such as kids' rooms and hallways."
All you have to do is write to the magazine with a few snapshots, details of what you want and your budget. Buy a copy of the magazine first to make sure you like its style.
Another approach is to get your house used in a photo shoot for some of the upmarket shop catalogues.
Pleun Van Akkerveeken, at Laura Ashley, says: "We try to use real people's homes in our catalogues instead of studios because it's better to have a lived-in look. We don't want `twee', and places have to be both quite unusual and not too small."
The company will decorate the room for free and let you keep fabrics and fittings but not the furniture. All you have to do is send some pictures to the company's creative department.
Habitat is another company that is interested in finding real homes to use for publicity. It shoots its catalogue in France but is always on the look-out for properties that can be used for press launches.
The house in question does not have to be vast, but big enough to hold about 100 people at a time. In return you'll get your house decorated in that season's look.
But be warned, not all companies do it: Marks & Spencer was very sniffy when asked, as was Liberty.
q Contacts: Kitchen Specialists Association, PO Box 311, Worcester WR1 1DR; Glass and Glazing Federation, 44-48 Borough High Street, London SE1 1XB.