can someone help me understand tax?

i have been wanting to earn a bit of extra money online whilst i look for a proper part time job (at the moment there is nothing available in my area). therefore i have signed up to several survey sites to get paid to do surveys for them, also this site where i can sell my revision notes, i also have a few items listed on ebay and am planning to go to a car boot sale to sell some other junk i've cleared out from my room. so my question is do i need to be paying tax for any of this? i have heard about a personal tax allowance of 10,000 per year and if i am right i don't need to pay any tax if i earn under this amount. the total of my earnings is extremely unlikely to reach anywhere near this amount and i am receiving no other income at this time.
also i am looking to make a bit of extra money doing some freelance writing on websites like iwriter and odesk (haven't decided on the specific website i want to use yet) and i was wondering if i need to pay tax or not for that (again i don't expect to be earning anything near my personal allowance)
i'd appreciate any insight into this cause i'm finding it very hard to understand on my own

Quite simply if your total income from all of these activities is less than £10,000 then you will not pay income tax.

However from a taxable income point of view, if you do things like surveys on a regular basis you could be deemed by HMRC to be self employed. The odd car boot sale or eBay trade is not deemed to be trading and therefore not taxable, however if you car boot every week or set up a regular eBay business this will become taxable.

Writing for cash is quite obviously self-employment.

There is room for differing opinions on trading (taxable) vs not trading so you should take advice from a local accountant if this stuff becomes anything more than pocket money.

so even if these surveys literally come to around £5?
Edit: i found this article on tax and it says that if my total earnings from surveys don't exceed my personal allowance along with all other earnings i don't pay tax http://www.moneymagpie.com/article/making-extra-money-do-i-have-to-pay-extra-tax