You get what you pay for. For ?40 you'll get a piece of crap. I have a cordless Makita hammer drill/driver and a cordless Makita impact driver for screwing. Both take the same battery - 18v 4ah. The higher the ah rating, the more grunt you get. Mine cost just under ?400 as a set but I am a tradesman and they are used everyday. I also have a mains powered Makita SDS for really hard walls. Anything by Black & Decker, Elu, Hitachi, in fact anything you can get in Homebase and B&Q are ok if you only need to use them once a year.