Ahh that's where your wrong, it's more important to you know than ever.
As you know you have to pay VAT on products that qualify for VAT whether you are VAT registered or not, so say you want to buy 5,000 A6 Flyers and the price is £80, if the company that you are purchasing from charges you VAT then the price you pay will then be £94, an extra £14 which you cannot claim back. 99% of the time (although there are exceptions) Flyers are VAT exempt and VAT should not be charged.
So make sure you are informed as to whether the products you are buying should have VAT applied or not, when you are VAT registered it will make no difference to you to be honest as you will just claim the VAT back.
The reason I chose to explain this on my blog is that I phoned Prontaprint last week to get an idea as to what they charge on A6 Flyers, ready for a local marketing campaign, I was amazed that on both occasions that I telephoned they said VAT was applicable, which in my particular case just wasn't true.
To me it wouldn't have mattered really as I would have claimed the VAT back but for the un-informed member of the public that isn't VAT registered they would have paid an extra £57.75 in this case which is disgusting, would that VAT have been handed over to HMCE or pocketed, who knows!