For a bitcoin node and not a lightning node, you can use, for example, a Raspberry Pi with 2gb of RAM, and a 1Tb HDD. You can find cheap laptops that allow you to extend the storage capacity. You can use them too. Rasp's solution is cheaper, either because it doesn't need to be the latest version, or because it only consumes 30 watts/hour. With that, you can download a debian version for Rasp, but if you don't have a background in the area, I recommend downloading for example Umbrel (https://umbrel.com/) or Citadel (https://runcitadel.space/). Just install them, download Bitcoin Node and Electrum Server to connect your node to your applications and that's it.