My site is still under construction (www.emigratetv.com) but we will be selling DVDs only. I signed up with Paypal but we are going to be offering a discount price through an advert in one magazine only. Is there an e-commerce site which will, at the checkout stage, enable customers to enter a voucher code (which we will give in the magazine) which then will calculate a discount price for them. (I do need something VERY user-friendly). I don't mind paying for it, but would prefer a one-off payment rather than monthly.