I hate buying lunch out, so I try to always have lunch made or leftovers ready to go in the morning. If buying lunch costs something like $4 – $8 depending on where you go, if you did that every day that’s $20 – $40 a week! Not to mention probably a lot of plastic. Making your own is better for your wallet, the environment, and is usually healthier.
But, for the times I don’t manage to get it together, I like to have “emergency” burritos in the freezer. I usually make a few at a time, wrap in foil (which you can reuse when its done, and depending on your city, recycle if it’s clean), and stick in the freezer and forget about them until you realize you have to run out the door and don’t have a lunch to bring! The beauty is you can literally fill them with whatever you want, I often do a kitchen-sink kind of thing where I just take stock of what I have already and combine. (My most recent batch were tahini, spiced chickpeas, kale, and roasted sweet potato).
Another life/money-saving trick is making snacks and freezing them – my favorite is these No-Bake Peanut Butter & Jelly protein bites from Minimalist Baker which I freeze and then I’ll take 2 with me for a good snack at work or class.