Can I get premium membership to SA for just a month?? Also can I use of loaded visa gift card as payment??
Yes, you can sign up for just one month - subscriptions auto-renew, but you can just cancel as soon as you sign up, you'll still get the full month you've already paid for.
In my experience, no, you won't be able to use a prepaid Visa gift card to pay for a membership.
I always use a visa gift card. Sometimes you may have to contact customer service to manually process it.