If I purchase a product over the internet from the UK, should I be charged VAT at their rate? If the product is stopped by customs would I also have to pay Irish VAT on top of it?
Depends. If the company does more than a certain amount of business in/to any EU country (c. €50K p.a. I think?) then they are obliged to charge the VAT rate of that country and not UK VAT (which may be lower). Once you have paid the relevant VAT rate then no further tax liabilty should arise on import as far as I know.
Thanks ClubMan, I just want to buy cosmetics which are not on sale here. One site charges 17.5% vat (UK) rate and another (NI) site charges the same amount of sterling for the product but doesn't specify that its VAT inclusive. Think I'll go for UK site as, if customs stops the parcel, I'll have a receipt which shows I already paid tax.