I have to shoot a big award show next week and have to take some “red carpet pictures”. I have a lot of experience taking event pictures etc. but I have never done portraits or used light boxes or any other lights. I guess I need some good light for the red carpet set-up and found some cheap softboxes - 2 for 100$. They have a temperature of 6500 kelvin - is this a good solution? Should I invest in more expensive lightboxes where I have more control over the temperature?
A softbox is just a light modifier and it has a relatively simple job; softboxes can be made DIY style with household materials and still work fine.
What matters more is the light source you’re using inside the softbox. If that’s also included in that price, it’s probably something like CFL bulbs which are going to be very weak for portrait work.
https://www.reddit.com/r/photography/wiki/buying#wiki_continuous_or_flash.3F
That just tells you about the light color, which you could also freely adjust using your camera’s white balance setting, if you’re shooting digital instead of film.
You want better light sources with higher output and more control over output.
Color temperature control in the light isn’t important unless you need to mix or balance that in a specific way relative to other light sources in the scene The camera’s white balance can’t help you there because that’s a global setting that applies equally to everything in the scene.