These days there are many credit cards which reward you with points or cash back for however much you spend on it. If you are still using cash to buy everything, or using a credit/debit card without rewards, you NEED to apply for one of these cards. It is basically free money!
For example, one of my rewards cards, the Chase Sapphire, gives me 1 point for every dollar I spend. These points can be used for shopping, travel, etc on Chase’s ultimate rewards website. Let’s say you spend $500 a month, and put it all on the credit card. Over a year, you’ll have spent 12×500 = $6000. The way the points translate in this case, it’s about a 100 point = $1 in value, so 6000 points would be $60. Not bad for doing nothing right? The 1% back is pretty typical, and many other cards, american express, mastercard, etc will have similar cards. They also have rewards cards that have much better benefits, such has higher % of money back, but usually they will come with a yearly fee, so you would need to assess whether you actually spend enough to justify paying the yearly fee.
Many of the cards also come with huge sign up bonuses, for example, 40000 points if you sign up and spend some amount within the first 3 months. Usually it is a large amount you need to spend, but if you can time it so that you get the card around the same time you’re about to make a large purchase, then it can work out pretty nicely. With the sheer number of options out there, you shouldn’t have trouble finding a card that works for you.
You just need to make sure that you don’t spend extra because of the card, or leave too big a balance on it because the interest rate is very high. The idea is to use it as if it is cash, so only with money that you already have. If it’s money you are already spending, might as well get a little bit more out of it!