Tax - Would i have to pay...?

Ok, i am setting up a home business i am hoping to fix peoples computers and earn money from it.

If i was to sell products like USB Camera's but not buying in bulk just buy for say 拢29 and sell for 拢38(拢49.99 in PCWorld) would that make me have to pay tax?

I need to know what makes me have to pay tax... what i can do to avoid having to pay but earning.

Note: I Am 17, 18 next year....

I need all the information you can think off...

You cannot avoid tax - we all have to pay it!
You need to register as self employed within 3 months of starting. The reason for this is that you will be liable to class 2 NIC's, which are payable by monthly direct debit.
You will pay tax on any profits you make over 拢5225 in the current year. Your profit is your takings, ie your charges to customers, price you are charging for hardware, less your expenses which include the price you pay for hardware.
You wont need to register for VAT until your takings exceed 拢64,000 in any 12 month period.
I think you need to ask your local tax office if there are any workshops for the newly self employed going on locally, or else see if you can find a friendly local business who will show you how to keep proper records for tax.

Any earnings over 拢5225 in the current tax year will be taxed. You also need to register with HMRC within three months of starting this "business". See http://www.hmrc.gov.uk for more info. Get the legal stuff right first before worrying about tax evasion.

If you set up a business, you will have to pay tax on your profits - the dfference between the sales the business makes and the business expenses it pays out.

This will be the same whether you operate a repair business or also make sales

I would take the first answer from snettert, this is good advice

Try making an appintment at your local bank and/or tax office, they will be able to give you advice. You will possibly have to register as a small business and register for VAT. As well as having the disadvantage of having to pay tax, there will be benefits too (claiming refunds on VAT and being able to claim back tax on the cost of workspace, stationery, in fact anything you have to buy/use in your business). No one can force you to pay tax, but if the taxman finds out, you could be in lots of trouble.