Ok, I know these questions may sound stupid, but being from the US, I just have no idea.

What is the VAT tax? Why do you have to pay that at the post office? Would that only be on something mailed from the US, or say, Iceland also? If I sent something from Iceland (a real Icelandic post office, not US) to the UK, would I just pay postage or what? Reason being, I have LOTS of Creatinve and EZ Flow items to sell (I changed to Tammy Taylor) and I wanted to give someone here a chance instead of selling it on ebay, but I am just not sure how things work over here. If anyone can help me out that would be great.

VAT is a UK tax. In the UK we pay VAT on items we purchase for business use. As a business if you are registered for VAT (turnover of over £52,000 I think) then you would charge VAT on your sales.

If I buy from the US then when it arrives in the UK I have to pay VAT and also customs clearance charges.

If you are selling your items then you would need to make sure that the transport method complied with the relevant regulations in terms of flammables etc. The person receiving the goods (in the UK) would be liable for the import taxes if it was worth over a certain amount.

This is how I understand it.

Hope that helps.