The first thing I would say is never ever attempt to fit carpet on your own. Even if you are fitting a very cheap carpet then still employ a professional to do it. As if you get it wrong then it will cost you very dearly!
Most carpet shops virtually throw in the carpet fitting for free. So why waste your time and money on going and renting a van, picking your carpet up, bringing it home, and then struggling to fit it as you do not have the skills to do so.
If you buy a new carpet then always employ a professional to do so. For a high-grade carpet you can pay over £50 per square metre. If you were to fit an average size carpet of 20 square metres and you were to make a mistake when cutting the carpet, and cut the carpet too short then it could easily cost you over a thousand pounds. Or add a few hundred more if you do the same to the carpet underlay.
Another thing is when laying carpet you do need the right tools for the job, and they are not cheap. For a start you will need a carpet knee kicker to stretch out your carpet and these will cost around £70.
You will also need a very sharp knife, and a good tape measure, as well as gripper rods, and a hammer and carpet tacks to lay them with. All of which add up, indeed you can roughly add at least £150 in carpet laying tools alone, on top of your carpet purchase. Then you also have the gripper rods and the underlay to take into account, which can add up to a big bill.
So you see that it is far more efficient and effective to employ a professional carpet fitter than it is to try and do the job yourself.
Employing a professional to do the job also buys peace of mind, as if they make a mistake and cut the carpet short it is their fault not yours, and as long as they are insured then it is their problem to sort out, not yours. Always check your carpet fitters insurance. If in doubt ask, as any good carpet fitter will provide them easily. If they do not, or they make an excuse for not providing it, then walk away.
Buying any carpet is not cheap, so buy peace of mind as well as anything else.