There are a few options for buying games for Atari 2600. One option is to check online marketplaces such as eBay, Amazon, or Etsy, where you can find both new and used games. Another option is to visit retro gaming stores, both online and in-person, which often carry a variety of Atari 2600 games. You can also check out local garage sales, flea markets, or thrift stores, as sometimes you can find vintage games at a lower price. Ultimately, it depends on your personal preference and availability of options in your area.