If you want to save more money you essentially have two options, make more, or spend less. The former is much more difficult than the latter. Making more money can be difficult in a tough economy, and it mostly depends on your education and skill set, which take time to develop. However, spending less money can be much easier than you think. So much so, that you might be able to keep your consumption level while spending less on it.
I will say that I take an issue with calling them “gift” cards, because they are better used on yourself rather than gifting them away. I say this assuming that you are buying them second hand and not from the original retailer at face value. From discounted movie tickets, to discounted dinner bills, you can find a several gift cards for all major retailers for as little as 80% of the value of the card. Those are built in savings. I can purchase gas cards, similar to diesel fuel card solutions in Europe, for a fraction of the original price. I can turn an $80 full tank of gas into $70, and over time those savings can really add up.
There are so many discount gift card sites out there that I’m not going to take the time to tell you which ones to use. There are several reputable ones that have had copious amounts of national coverage on them. Simply Google “discounted gift cards”, and check the news listings on those sites, and you are sure to find several reputable sites to choose from.