I'd maybe consider spraying just a light Orange-peel texture on a "Regularly" primed wall. I'm gettin' very good with just the spray-cans of texture!!
I've coached some customers of ours on this, and some have thanked me!
This MAY be an option if your wall-areas aren't too big.
For a higher-end look, skim the walls smooth, and, yes....sand again
This obviously takes a practiced hand!! I'd at least get a couple estimates!
Once done though...you'll be glad!
You'll be adding $value to your home if done well, so there IS kind of a payback if ya look at the bigger picture.