If you are looking for a cheap run around then you may see there are lots of vehicles advertised for sale with no MOT. An MOT test can cost as little as £20 but you may find that the car needs a lot of work doing on it in order for it to pass.
Often people advertise cars with no MOT stating that it should pass with no work, or it may only need a new tyre etc. to pass. Be very wary relying on this as often if they are that confident it would pass with very little work needed then they would put an MOT on as they will be able to sell it for more money with 12 months MOT.
If you buy the car knowing it has no MOT and then it fails on a number of things you will usually not be able to return the car and may have lost your money.