How to add the functionality of a gift certificate in VirtueMart?

I am creating an online shop using VirtueMart. Now I want to add facility of a gift card as we have in Magento开发者_StackOverflow中文版 and OsCommerce. So is there any plugin available in VirtueMart or do I have to customize VirtueMart ?

VM does not do Magento/OSC style gift certificates without an extension. It does support simple coupons, but they are pretty limited in how they work. Your best bet is to use AwoCoupon, it's free.

http://extensions.joomla.org/extensions/extension-specific/virtuemart-extensions/virtuemart-coupons/11629

I think you are looking for variable price component wherein user can enter the amount of gift certificate in the product. I don't think there is any module which will do in Virtuemart. I was also looking for this in January this year in Virtuemart so after exhaustive search I finally moved to Ubercart which has pretty good support of this feature.

You need a third party plugin to do this, Virtuemart does not have this feature out of the box. Try https://www.osignite.com/software/vm2-gift-certificate.html