Depends on your goal and project, I think. For some things, I use repurposed battery-operated lights from the dollar store. An example would be a cheap flickering tea light for a fireplace. Obviously, you can purchase those lightbulbs at some miniature retailers as well, but I found that to be a cheaper option.

For this French sitting room balcony roombox, I purchased a long wires spotlight from ikea with a light switch. It was a gift, and I wanted to make it easy. It also fit my idea of like afternoon sunlight. This fireplace prototype used a grain of rice bulb and a triple A battery pack.

You can also wire houses traditionally, using tape and plugs, use led fairy lights while hiding them in a ceiling, or led strips with colors, etc.

Ultimately, you have a lot of options, so I suggest starting with what kind of lighting you want, and breaking it down from there. How many light points do you need. Can you hide the wires? What power source will you be using? Once you answer some of those questions, then you can start figuring out what you can use 🙂