Avoid Oxford Street at the weekends, especially in Summer as it is super busy. For designer shops (window shopping) go to Knightsbridge or the King’s Road, Sloane Square.
in my opinion, more expensive supermarkets are-
Waitrose, Sainsbury’s and Tesco. That said, they are good for speciality foods, as is M & S Food.
Middle of the range:
Asda and Morrisons
Lidl, Iceland (mainly frozen but has some fresh and tinned food) and Aldi
Wilko and shops such as Poundland
Superdrug; even wider range with more top end names: Boots
* these opinions regarding shopping prices are based on my own personal experiences, it can of course vary depending on what you buy and what offers are on.
Paying for transport:
You can queue up but perhaps a better idea for when you have arrived is an Oyster Card or a ‘visitor Oyster card’. Go to the TfL (transport for London website) to check out Oyster cards and for planning your journey around London. You can top it up at stations and newsagents with the oyster sign. If you have a contactless card, you may be able to use it to pay for your travel around London, but it’s not guaranteed.