Visiting UK for first time

[Feronix]

I'd take this:
https://www.stanstedexpress.com/?gc...kAGLM49M9DQNAdAyJ60CpJmb7n79QS0zeaxoCYxjw_wcB

Will cost you £20 max for a single, or £32 max for a return but there are usually cheaper offers available on the site (like I randomly picked the date of March 6th and there was a single for £12).

Then once in London, get yourself a daypass for the tube for £8 a day and you get unlimited rides to any destination within London. If you chose to be dropped off at Liverpool Str, that is literally in front of the central station

 

[Greenback]

If you are going to be traveling around London I'd look at getting a travelcard it lets you on tube and buses, I looked on trainline and they were about £17 from Romford not sure if that's all zones though