It requires a bit of financial discipline, but having a credit card that you religiously pay off in full every month can be a really powerful budgeting tool when money is tight. It lets you combine paychecks or borrow from a future week's budget so you can take advantage of bulk prices or a really good sale price to stock up on things you use a lot of. And once you get stocked up on all your staple items, the money you would have spent on those things gets freed up for other things for weeks, or maybe even months at a time.

Speaking of stocking up on bulk items, my Costco membership has saved me a ton of money since I've had it. It might not make the best budgetary sense for everyone, but my membership fee more than pays for itself just with what I save on gasoline. Even when they don't have the best price on something, often the quality you get for the price still makes a lot of their stuff worth it for me. But even if I don't find a deal on something it's always nice to be able to grab a huge rotisserie chicken that I can make meals out of for most of a week for $4.99.