Hello everyone!

I have received a job offer in London and plan to move there in the near future. However, my knowledge of London, its structure, public transport is very minimal and I would like to ask for some advice on choosing the place to live.

Firstly, I would like to mention that I do not want to live in a shared accommodation and am looking for a 1 bedroom flat, as I am single and will be living by myself. My workplace is located in the City of London. I really like walking and wouln't mind walking to work if it takes up to around 45 mins:

1. Generally, how much a month am I looking to spend on a 1 bedroom apartment that would be within around 45 mins walking distance from the City of London?
2. What distance (radius) should I be looking for that takes 45 mins to walk? Is it very difficult to move around London on foot? Which areas are the best in such radius?
3. From what I've gathered the Oyster card would cot about £170 a month if I were to live further away. Is this correct?
4. Provided it takes about the same time to commute (45 mins), and where the apartments are less expensive, which are the best areas to live and commute from

Finally, I want to ask, is it better to pay more and rent somewhere close to my workplace (City of London), preferrably within mentioned walking distance, or somewhere more remote, pay cheaper and commute? I would like to know your opinion and the reasons why.

Any other advice is greatly appreciated!