Data point: Going through fatwallet, 1% cashback for Visa/Mastercard giftcards on giftcards.com - $3000 giftcards purchased in August - cashback of $30 paid today (so takes about 90 days).

$500 giftcard has a fee of $5.95 - $5.00 cashback from fatwallet = $0.95 nett cost per $500.

There are free shipping codes available quite often to save a few dollars.