As previously mentioned, not all games are super expensive. They may be free, or only cost like $20. If you play on console, game subscription services are possible. These cost money themselves, but offer many more free or cheaper games. My final point is that there is beta testing and early access. Although this is very unreliable, if you're able to play the game in beta then you'll get a feel for it and see if you want to buy it.
Not having enough money to buy the expensive games is really my entire point. Especially as a teenager, getting a job can earn you money that can be spent on things you want, rather than necessities when you're an adult. Technically my next point was mentioned above, but I expanded it. There are so many options for free games around the web. If you're just using one or two gaming sites, consider using more; there could be some game that you'll fall in love with. My final point could be a solution to finding cheaper games. There are places such as GameStop or Ebay or another platform that lets users sell their items. Sometimes, those items are pre-owned, used games that may sell for cheaper because they're not factory new. This could save you so much money if you find the right seller.