We've found that it's far cheaper to buy plain food than anything packaged or prepared. A box of pasta and pasta sauce is usually cheaper than in equivalent about of canned stuff, though it's not always as good.
I don't eat a lot of condiments, but I could get by on snagging stuff everytime the opportunity showed up. For instance, pocketing sugar packets if I was at a restaurant, or asking for extra ketchup, mustard, etc. if I happen to get fast food. My mom and I always have tea when we are out, but I like strong tea and she likes weak so we would use the same bag and stash the other one for later at home.
I don't much about cooking, but I picked up enough basic things to cook vegetables and such, which for me was worlds cheaper than buying mucrowave meals. Oddly, less of a hassle too.
We're okay for money here, but sometimes things stretch pretty close to the line. I saved a lot of money a few years ago so I'm running off that while I'm looking for another job or more school. I'm very glad I was living frugal back then.