Your best bet would be to use paypal in combo with the visa gift card, just use it as a normal credit card for the amount that it has on it, you dont have to use the whole amount.

Google Checkout. Make sure to activate the gift card on the card's website. If that dosnt work maybe try Gocash. Some cards worked for me some didnt.

I had a same problem.

You just need to pick Paypal as your payment method first.
It will lead you into the page that asks for paypal account and password.
However, if you pick the option that you do not have a paypal account, it will lead you into the page that only has card input information.
It will work just as same as any other website using Visa, Master etc.

I think it depends on the bank that issues the giftcard. I had a couple work on google checkout and a couple that annoyingly didnt. I prefer to use gift Visas for online purchases myself for security reasons and not having to worry about something I didnt buy charged to my account. For NF I use Gocash now though.