When I lived in the U.K. when I was in college, my flatmates and I would shop at Tesco all the time. The one near the university was quite large, comparable to Safeway in the US.
This Tesco is an "express" is small, but they do have the basics like , breads, grains, meat, dairy, canned goods, some veggies, cleaning products, sodas, crisps and candy. They have a nice selection of cold English ales and wine from the continent. You can easily find bottles of wine under £10. Hard alcohol are located behind the cashiers so you'll have to ask for those. There are also magazines by the register. They do have some basic toiletries, but i would go next door to the Chemist if you need health and beauty products!
We got some water for our hotel room, about 50p for a liter which is not a bad price. We also got our favorite Cadbury bars. The Cadbury bars taste different here than the ones in the US. Here they have Wispa, Twirl and Flake which are my favorite bar. read more