There are literally more free games to play than there is time to play.
Most obviously, there’s plenty of free-to-play games, on PC, console and mobile. Games like Fortnite, League of Legends, Rocket League, Clash Royale, Hearthstone, Apex Legends, GenshinImpact and so on are high-quality games that you can play for years without paying a dime.
The internet also has free game portals like Kongregate and Addicting Games which have been around forever. Be careful of scammy game portals though.
If the microtransactions that often come with free-to-play games concern you, there are also plenty of free downloadable games available on major platforms and, if you’re patient, games on digital stores like Steam, Epic, GOG, Humble Store, itch.io etc will have games that are made free from time to time. Heck, Epic even gives out free games on a schedule, every week. If this sounds attractive, the freegamestuff subredditis a good source of information for games that go free.
This doesn’t even count the thousands of free mobile games available to download on the major app stores (e.g. Apple App Store and Google Play).
From there, your options only expand as you spend a little money. And even without money of your own, asking to be gifted gift cards to these services for birthdays, Christmas and so on will get you a lot of value.
If your parents are Amazon Prime subscribers, it’s also worth noting Amazon Prime gives access to Twitch Prime which also gives away a few months each month to members. Likewise, if you own a console and are a PSN or Xbox Live member, you also have access to free games each month.
Several of the major platforms also have games subscriptions such as Apple Arcade, Playstation Now, Xbox Games Pass, Humble Choice and so on which allow access to a lot of games for a monthly fee. In many cases, these subscriptions are all-you-can-play.
If you’re willing to spend even a little, digital saleson sites like Steam, GOG, Epic Game Store, etc mean there’s access to hundreds of games for as low as $1. Most gamers tend to have incredible backlogs of games on Steam, just because of these sales. I personally have a few dozen games I will probably never get around to playing.
In that vein you’ll also get a lot of mileage out of game bundles. Humble Bundle, for example, famously allows you to pay what you want to charity for several games. If you want to check for new game bundles, the gamebundles subreddit is a good source of info.
Lastly, I’m sure you’ll be tempted to go down the illegal piracy route. This is especially true since playing games for free often involves passing over the biggest and newest releases. Given how many great games you can often get for nothing or next to nothing, I advocate not giving in and going down this route but honestly, I readily admit if you’re going to do it, a stranger on the internet telling you no isn’t going to stop you.