so if i got a computer case for example from my supplier for say £16.25 and with vat it is £19.50...... but i sell it at say £25 with no vat. if i voluntarily registered for vat could i not claim back the vat from my supplier?
As soon as you register for VAT your sales will need to have VAT added - almost everything you sell will have to have VAT added
So you buy the case from your supplier at £19.50, you reclaim £3.25 VAT but you now sell that item at say £20 + VAT (£24) in simple terms you hand the Vat man £0.75p the difference between your incoming VAT and your outgoing VAT, the profit for you is £3.75 but if your not VAT registered you buy at £19.50 and sell at £24 your profit is £4.50.
The downside is if most of your clients are VAT registered they will want to be able to reclaim VAT from your invoices which they cant do unless you are registered.
But wait a minute the story doesnt end there - if you are not VAT registered and dont reclaim from your suppliers then this is an expenditure and is offset against tax so you win again.
As others have said zero rated only applies to certain goods and computer equipment is not one of them
Registering for VAT should never be done unless necessary or by consultation with an accountant