We will be taking amateur photos of people for a graduation, and were wondering about light kits. Without the kits the photos can look dull- what kind of lighting should we be using? We want a cheap option and to not have to be connected to a power source. What would you recommend?
If you can find a large north facing window, you can eliminate purchasing any lighting kit. This is a good place to start.
With a single flash and a white wall, you have a great lighting source.
Finally, put the flash into an umbrella close to the subject with a reflector on the other side.
In my gear I have a Nissin Di866 Mark II with Power Pack PS-300, Yongnuo YN-622C along with a reflective umbrella.
I found useful suggestions on an article in Petapixel. I would choose for such an occasion to find a White Seamless in Hallway and give a bright feeling to the portrait as it is a happy day!
If you prefer to keep the background (banners, etc) as part of the photo I would suggest the use of an shoot through umbrella, in order to defuse and even the light coming from the flash.
More quick details on the umbrellas you could find on the following article, Umbrella 101 for Beginners: Bare Flash vs. Shoot Thru vs. Reflective Umbrellas