Construction lights are mostly heaters. Most films (everything except extended-red stuff like SFX200 and aerial surveillance films) don't respond well to light that red, they're a fire risk (especially near diffusion material for softening) and they're unbearable for portrait subjects in warm climates.
If you want to start out cheap, get a big old manual hotshoe flash. You'll still find it useful as a secondary light later on when you buy a proper monolight, e.g. for use as a hair light, background spot or fill.