Driving test: I agree with lyonaria. Get an app to help you study for the theory test. The subject matter covered is extensive, and you'll want to take some time to really be sure you're familiar with all of it, because you don't know which questions they'll ask when you get into the test center on the day. Also, find a preparation system that has interactive video clips for the hazard perception test, so you can practice clicking them at the right time to get the most points. I cannot stress this enough. You need to know what that portion of the test is before you show up to take it, or you could end up with no points at all.
The practical is just really fussy. You have to learn how they want you to handle the car, and you have to do it exactly their way, every time. Also, shifting with the left hand is weird. If you will test in a manual, you'll want lessons just to get used to being on the wrong side of the road, car, and shifter. Everything is backwards, and it takes the brain a while to acclimate to it. And, while you're practicing that, you might as well get an instructor to tell you what you need to know to pass the test. Oh! And at your practical, there are a few car safety/maintenance check questions they will ask you. Learn those.
I passed my theory and practical on my first tries, after buying an app to help me study for the practical and taking 6 hours of driving lessons. My costs to get a full license in the UK were:
£43 - provisional license fee
£12 - theory test and hazard perception prep software
£23 - theory test
£62 - practical test
£152 - driving instructor (lessons + test day)
So, £292, total. I don't think it can be done for less than that, honestly.