Tesco have recently been supplying a large number of sports supplements in stores, as have other high street retailers such as a Argos. In some cases the prices are relatively competitive, and although they struggle to match some of the prices available online, there is a convenience element of just being able to nip in to Tesco and pick up some supplements if you run out.
However they recently had a very good offer on USN products, including USN Muscle Fuel Anabolic which was reduced to £27.50 for a 2kg tub! Although this offer has ended, they are now offering significant reductions on their range of Sci Mx products, with approximately 30% of most of the range. This offer does not appear to be reflected online, so unfortunately you will have to go in store to buy the products.