Moving questions in London

Due to general pressures from mummy dearest and having wanted to get out for years, and finally having a full time job that will enable me to do this (as soon as I combat the scary credit cards sometime soon - I was looking at Gumtree and the whole '4 weeks rent + deposit in advance' had me going 'but... but... 800 quid? :wails: - it turns out the cost is looking around 55-90 quid max on my wages) and having no idea on regions, I'm wondering about advice on areas in London and other good sources for flatshares?

I'm currently looking at north of the river, zone 1 or 2 to cut down on travel costs and time (also possibility of walking to work in the mornings if I'm desparate/transport system fucks up) as I work in Regents Park/Oxford Circus/Goodge st area.

Of course, there's also the whole going round flats/getting all my junk to London somehow thing to factor in, but that's currently being pushed to back of brain.