Re: quick business lesson please :P ?
You dont need to pay tax if you earn less than £7475 per annum in TOTAL.
Being self employed, you will need to file a tax return before the end of the financial year. Also, if you have a part time job, that is included in your total earnings.
If you earn between £137-£817 a week, you pay 12% National Insurance.
If you earn from £7475-£35k a year, you will pay 20% income tax.
I think that about covers it.